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P1797 Neutral Safety Switch and ESC Please Advise

28953 Views 57 Replies 5 Participants Last post by  AllanC
Hello, I am having two issues and they could be related but I am not sure. The only code I am getting is the P1797. Please advise as to where this switch is and how can I replace it. I have searched out this switch online but have failed to find that this switch is actually even used on my 2011 Dodge Grand Caravan. Symptoms are that it is difficult to shift the lever out of park and if the ELECTRONIC STABILITY CONTROL light is on, is on then this is when I have the problem. I must power down and restart in order to start. I am afraid eventually it will fail completely.

I am wondering what this ECS which has a button on the front console on the same panel as the hazard lights is coming on? When I push the button, it seems to do nothing. Why is this light coming on? What can I do to correct this issue?
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. . . . The only code I am getting is the P1797. Please advise as to where this switch is and how can I replace it. I have searched out this switch online but have failed to find that this switch is actually even used on my 2011 Dodge Grand Caravan. . . .
You can do an internet search on diagnostic code P1797. You will find information that indicates there is a malfunction with the Park / Neutral switch. On the 62TE automatic transaxle in your vehicle there is no Park / Neutral safety switch. There is a transmission range sensor that sends binary signals / ON, OFF to the PCM (powertrain control module). A rationality check is performed on the transmission range sensor signals and that is how the logic knows which range / gear the transmission is currently operating.

However I did a review in a Chilton service manual for 2011 Dodge Grand Caravan and it indicates that code P1797 is associated with manual shift overheating in the transmission. So this is confusing. Maybe others can specifically identify the condition related to code P1797.

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Good find. It is always nice to have an image showing where parts are located.

I am still questioning the interpretation of code P1797. When OBD II was established codes P0000 --> P0999 were generic and used by all manufacturers to indicate the same type of fault / device / failure / etc. Codes P1000 --> P 19999 are manufacturer specific. So Chrysler code P1797 will not necessarily mean the same as another manufacturer's code P1797. In fact I did an internet search and found one manufacturer where P1797 indicates a crankshaft position sensor failure.

To the original poster concerned about getting stranded and NOT being able to move the shift lever from the PARK position:

Go to this link and view the video on how to override the shift lever interlock and move the shift lever. Vehicle is a 2009 VW Routan which is really a rebadged Dodge Grand Caravan sold by VW. Go to time interval 21:28 to see and listen to the comment about override.


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. . . . Thanks but it would have been better if it was on the 62TE, this picture shows the TRS on a 41TE I hope it is the same location on the 62TE
I agree that the image labeling is misleading. Even though it states 41TE I believe the image is a 62TE. My reason for believing this is because it shows a variable line pressure solenoid adjacent to the TRS sensor plug. The 41TE transaxle did not have this additional line pressure solenoid. Besides this the 62TE is physically very close in design to the 41TE so expect the TRS and other components to be in virtually identical in location.

. . . Thank you for replying I have a feeling it is the TRS . I also think it will probably eventually not shift out of park
You need to perform this test / observation before condemning the TRS. Turn the ignition switch to ON / RUN. In the lower part of the speedometer housing the P R N D will illuminate. If the transmission shifter is in PARK position, there should be a rectangle outlining the P. As you move the shifter to R, N, and D positions the rectangle outline will move to each letter in sequence. Does this happen? If YES then the TRS is functioning properly and has NOT failed. How does one know this?

Moving the shift lever actuates a mechanical control cable on the transmission valve body. On the actuator arm inside the transmission and near the valve body, there are 4 cams that move and open and close 4 logic sense switches: T42, T41, T3, T1. These 4 switches aggregated together represent a digital code for each gear selector position. The PCM interprets this binary code and sends the appropriate signal to the instrument cluster module to display P or R ro N or D. If these 4 switches were not functioning properly nor was the digital code interpreted correctly, you would see something wrong. For instance with the selector In PARK position the R would be highlighted or if the shifter was in D position, N would be highlighted. If the P R N D display illumination matches where the shifter lever is positioned, the TRS mechanism is working correctly and NOT the cause of the stuck shifter.

Dose the cruise control function correctly? That is does the cruise disengage when depressing the brake pedal? If it does that correctly then the brake sense function is being monitored correctly by the PCM. The TRS digistal sense code and the brake sense code are sent over the vehicle network to the wireless control module. The wireless module controls the unlocking feature of the shifter.

Does the vehicle have keyless entry where you use a remote key fob to lock and unlock the doors? Does the remote lock and unlock feature work properly? If YES then you know that the wireless control module is communicating over the vehicle network. It receives the command, lock or unlock, via digital air transmission, interprets the command and then sends the appropriate signal over the network to the receiving device to lock or unlock. If this is happening then there is no lack of communication between modules and that is not the reason for the stuck shifter.

I am thinking that there is a potential mechanical problem in the shifter such as a stuck cam or the locking solenoid has a poor wiring connection.

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. . . . ok, I shifted it i to each gear and each gear illuminated. There is no box outline though, just as it shifts green park reverse red, Neutral is green and Drive is green. . . . .
You performed the TRS sense switch test and all gear positions on the instrument panel illuminate as expected. So your TRS is working properly. No need to replace it. The sticking shifter lever that will not exit PARK position is NOT attributable to a failed TRS.

. . . The key fob isnt that old. i have to buy another one. But,sometimes i have to hit it several times before it unlocks the door. . . .
I believe the remote key fob unlock procedure works like this on Chrysler Corp vehicles. Press the UNLOCK button once; only the driver door unlocks. All other doors remain locked. Press the unlock button for the second time and the remaining doors unlock. I believe this is the situation you are encountering and this is how the system is designed to function.

. . . . I do not use the cruise control but, i will check it one i start moving again. I am in the Queue at dfw airport. . . .
I suspect that the cruise may not function properly or engage / disengage due to problems with the brake light switch. But test the cruise control when you have the opportunity and report back.

. . . But, as I stated just half an hour ago, I got 4 codes all related to brake switch. but a coupke of weeks ago when i replaced it, i was able to get the check engine light to go off. Today the po572 turned on the check engine light again. i purchased the brake switch at Oreilys. maybe I should get the Mopar. . . .
I think the brake light switch was not installed properly and the black plunger with button end that contacts the brake pedal arm is mis-adjusted / too short. I do not think you need a MOPAR brake light switch. It would need to be installed correctly.

I think the brake light switch is self adjusting upon installation. You only get one try at installation time to get it installed and adjusted correctly. Service procedures that I have found online allude to the fact that once installed but the plunger is not adjusted properly, you cannot remove and readjust the plunger. So maybe another brake light switch might be necessary. But let's continue to test and get definitive evidence before buying more parts. Why did you replace the original brake light switch?

With the vehicle parked start the engine. Immediately look under the dash at the brake pedal arm. Make sure the brake pedal arm is fully released and at its full rearward travel (ie brakes fully released). Look at the tail lamp assemblies at the rear. Are the brake lights turned on? If yes then the plunger button on the brake lamp switch has been retracted / pushed into the switch assembly too far and is not moving into the switch to open the sense circuit for the brake lamps. Check this and report back.

This is my best guess about the mis-adjusted switch. If other contributors have more detailed information about how the brake lamp switch should be installed please post.

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. . . . The switch is non-adjustable, but if it isn't installed correctly you will have problems. Once the plunger sets to the brake pedal height with the pedal resting on its upstop, that is the adjustment.
IC: Thanks for confirming my theory that you only get one attempt at adjustment on this switch.

In my research I ran across this video of a DIY mechanic and his explanation of a mis-adjusted brake light switch. Vehicle is a 2010 Jeep Wrangler and it uses the identical brake switch as does the 2011 Dodge Grand Caravan. The switch plunger gets depressed and shortened too much and this is what is keeping the brake lights on continuously. Start at interval 1:00 and watch. At time 2:20 he forces the plunger out. Hmmm. Maybe this is NOT the proper fix for such an important device safety wise on a vehicle???


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Ok, i did as you suggested and the pedal is in fact all the way out and i verified proper operation of the brake light.
I put in a new switch because a couple of weeks ago, i got the code po572. when i installed the sw i remember thinking that the plunger was too long and that it would not fit compared to the oem i took out but all i had to do was pressure either on the plunger or the bracket that it rest on in order to install the switch. . . . . .
I believe the proper installation procedure for the brake light switch is to depress the brake pedal and then install and rotate / lock the switch in the mounting bracket. Doing this prevents the EXTENDED plunger from contacting the brake pedal arm. Once the switch is locked into place, you release the brake pedal arm, the arm contacts the plunger pad and compresses it into the switch. The first movement of the plunger sets and adjusts its proper position. So I believe it is installed correctly.

Another simple test. When the brake pedal is depressed does the center, high mounted brake lamp illuminate and when released the high mounted brake lamp turns off?

I will give you a link to a dropbox folder that has 3 wiring schematics. Open the wiring diagram labeled fuses TIPM. Look under the hood at the TIPM and verify that the fuse in cavity M1 (rear center brake lamp) is good and has correct amp fuse. Likewise look at cavity 37 (antilock brakes, stability control, stop lamp) and it is proper and not blown.

It is tedious but I would check all the fuses and relays in the TIPM. If you look at the legend description, some fuses could be powering modules that might have some indirect influence on the diagnostic codes you are getting. The items labeled J are cartridge fuses and those labeled K are relays. Wiggle and make sure everything is seated properly and spade connectors are clean / not corroded. It is probably wishful thinking but sometimes in diagnosing problems the obvious approach gets overlooked.

Dropbox - 2011 Grand Caravan (at )

If you get to this point and the center high mounted brake lamp passes its test and all of the fuses and relays in the TIPM are satisfactory, I would remove the brake light switch and do some testing. Here is a link to a video that shows how to test the terminal of the brake light switch. Perform the test and determine if the brake light switch is still functioning properly. You will need a 12 volt powered test lamp or a volt-ohm meter that can check continuity in circuits.


In addition to the test shown in the video I would add this test. Seeing the orientation of the switch in the video with the switch plunger pointing to the left, mentally count and label the spade terminals from left to right in this fashion; 6 - 5 - 4 -3 - 2 - 1. With the plunger extended connect one lead of the test light / volt-ohm meter to terminal 6. In turn touch the other lead to terminal 4 , 3, 2, 1 in order. There should be NO continuity. Move the test lead to terminal 5. In turn touch the other lead to terminal 4, 3, 2, 1 in order. There should be NO continuity.

Repeat the above test with the plunger compressed. Press the plunger about 1/2 inch in. Use tape to hold the plunger into the switch assembly. Again touch a test light / meter lead to terminals 5 and 6 and in turn touch the other lead against terminals 4, 3, 2, 1 . There should be NO continuity. If the switch passes all these tests it is good. Installing an OEM switch is not going to fix this ongoing problem with code P0572 as you have tested and proven that the brake light switch is functioning properly. (I do NOT want to get into a discussion about the pros and cons of OEM parts versus aftermarket parts.)

If you get to this point and all testing still has not pinpointed a specific problem, then one is going to have to check wiring for open circuits, shorts to voltage or shorts to ground. In the dropbox link I have a document labeled P0572 diagnosis. It has a table of possible causes for code P0572. You would follow the diagnostic suggestions along with the diagram in document Brake Switch Wiring to PCM and trace the circuits.

Look at diagram Brake Switch Wiring to PCM. When the brake pedal is depressed the brake switch plunger extends and continuity is created between terminals 5 and 6 on the brake light switch. Terminal 5 is connected to ground and brake signal 1 wire is grounded. The PCM detects this and sends a message over the vehicle network to the TIPS to illuminate / turn on the rear brake lamps. When the pedal is released, the plunger is depressed and the circuit between terminals 5 and 6 is interrupted. The PCM detects this and tells the TIPM to cancel brake lamp illumination. However there is some intermittent condition (???) that is grounding signal wire 1 to the PCM on the dark green / white wire. The P0572 code indicates that the circuit from terminal 6 of the brake light switch is continually grounded and does not change state from OFF to ON and from OFF to ON. The PCM is getting logic confusion and thus does not send the proper signal to the wireless control module to unlock the shifter lever when the pedal is depressed and you attempt to move the shifter lever from PARK position. Shutting of the engine and then restarting temporarily clears the logic confusion or resets and the PCM sends the proper signal to the wireless control module to unlock the shifter when desired.

This is a lot to digest and the last part is my best guess as to theory of operation. View the video and perform all the brake light switch tests and then report back. Getting access to wiring and checking for shorts is a lot more involved.

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. . . Center High Mounted Lights work the Cruise control does not work
Good verification. This indicates that fuse M1 in the TIPM is good. When the brake pedal is depressed, the brake light plunger extends. Terminal 5 power from fuse M1 is connected to terminal 6 and onto the rear center high mounted stop lamp and onto a connector at the TIPM.

And I believe you indicated that when the brake pedal is depressed, the left rear and right rear brake lamps turn on? Is this correct?

If YES then the TIPM is receiving the proper signal to activate the brake lamps and the circuit through the brake light switch for controlling the brake lamps is functioning properly. So that circuit can be eliminated as a source of the issue.

. . . . Found out last night that the Cruise Control does not work. . . .
Since the adoption of drive by wire (electronic throttle control; no mechanical cable connection between accelerator pedal and throttle butterfly) the cruise control hardware has been simplified. Since you are able to drive the vehicle and the throttle works correctly, you know that the PCM is able to control the stepper motor at the throttle body and open and close the throttle butterfly valve.

Because the PCM has detected a brake sense signal circuit 1 problem, it is disabling the cruise control feature for safety reasons. If the P0572 code can be eliminated then the cruise control function will return.

. . . Also, it is becoming now more of an automatic thing that I have to do to shift gears out of park, I must either kill the power if I have already been driving or, I have to insert something into the square little access place right above the shift lever and press down to release shift lever so that I can move into drive . . .
In a recent post you mentioned hearing a constant clicking sound coming from the area of the transmission selector lever. I believe that the wireless control module is receiving false signals and applying a constant duty cycle to that transmission shift lever unlock solenoid. That is it is rapidly energizing and de-energizing the solenoid. Maybe the wireless control module is recognizing the rapid cycling and disabling cycling control to protect the solenoid? This solenoid is probably designed for intermittent duty and not constant duty. (This is a BIG guess!)

Next step is to check the ground terminal at the brake light switch. I believe it is terminal 2. Look for a wire that is black with red tracer or solid black. I have found some inconsistencies in wiring diagrams with wire colors so I am not sure. But I believe the ground wire is black with red tracer. Use a 12 volt test lamp and touch one lead to 12 volt power and the other to terminal 2 (black / red tracer wire). The test lamp bulb should illuminate brightly. If NO illumination there is an open ground circuit problem. If the bulb is dim then there is excessive resistance in the circuit to ground location G300. Report back.

Does anyone know where ground G300 is located? My resources are limited and I am not sure. Is G300 grounded on the floor under the driver's feet? Grounded to the left cowl? Grounded to the steering column? If there is a poor ground / no ground at the brake light switch terminal 2 then the location will need to be determined.

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, , , , but, what if the cruise control is not working?
Read my post at 12:55 pm Tuesday, Mar 14. When the problem is corrected that is setting code P0572, then the cruise control feature will start to work again.

. . . I checked J6 J7 J18 M1 M14 M18 M20 M27 M28 was going to check M33 and M37 but fuse puller broke will have to wait until i get home and get a needle nose. checked with ohmeter all are good. . . .
Very good to know. Continue to check remaining fuses.

. . . . all 3 lights in rear for brake work, when brake pedal is depressed
Very good. We now know definitely that the stop lamp circuit terminals 5 & 6 on the brake light switch are functioning properly. Center high mounted brake lamp illuminates and the TIPM is receiving the proper signal to illuminate / turn on the rear brake lamps.

. . . . I may have introduced another problem. I was checking the fuses with Acc power on. Now that i have it all back together. The AbS light is on steady. when acc or when running. So this is new
On the underneath side of the TIPM cover there is a legend that identifies all fuses, relays, etc and their location. Did you replace fuse M37? That controls power to ABS. In the dropbox folder that I posted at 9:59 pm on Monday, Mar 13 I added a file to the folder named Fuses M7 M37. Look at it and I highlighted where these fuses are located. Fuse M7 has only 1 location; not 2. I also show where the 12 volt power input to the TIPM is located.

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Continue with checking fuses for continuity.

Have you checked the fluid level in the automatic transmission? Incorrect fluid level (too high or too low) can cause heat buildup. There is a temperature sensor in the automatic transmission that monitors fluid temperature. Fluid that gets excessively hot can force the transmission controller to change the shift pattern and this is noticeable. Insufficient can cause delayed starts and engagement of clutches.

Look under the transmission at the pan. There are numerous bolts (about 14 - 16) that attach the pan to the aluminum case. Are there any signs of fluid leakage? Check the 2 flexible hoses that run from the side of the transmission that faces the radiator to the transmission cooler. There is probably a cooler in the radiator header tank and there may be an air to fluid heat exchanger in front of the radiator and A/C condenser. Make sure the transmission cooler hoses connections are clean, tight and show no signs of leakage. Are there leaks where the left front and right front axle shafts extend into the sides of the transmission? If there are any signs of leakage then the transmission could be low on fluid.

This is a link to an article on that describes how to check transmission fluid level.

The Chrysler 62TE automatic transmission (transaxle) (at )

The 62TE has a very short dipstick tube and was not intended for DIY owners to check the fluid. It very well might have a sealing cap on the end of the dipstick tube to prevent tampering. Scroll through the article and read about checking fluid level. There is a chart which needs to be consulted. You have to know the temperature of the fluid and then find the correct fluid level at that temperature. The author suggests using a short piece of old speedometer cable to check fluid level. You can use your engine oil dipstick also as a measuring device. Wipe it clean of engine oil, insert it into short filler tube. When it hits bottom of pan (you can tell by clunk) extract it and use tape measure to get fluid level depth.

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Go to the linked article I posted at 2:09 am on Wednesday, Mar 15. Scroll through the document and find the reference to a chart showing fluid level that shows transmission fluid level at various operating temperatures. I have repeated some of the chart information below.

Deg F Min level Max level

70 3 mm 1/8 in 14 mm 1/2 in

75 3.5 mm 1/8 in 16 mm 5/8 in

80 4mm 5/32 in 19 mm 3/4 in

200 40mm 1 9/16 in 54mm 2 1/8 in

Procedure to check transmission fluid level.

Make sure vehicle is on level surface.

Set parking brake firmly.

Start engine and let idle in PARK position.

Move selector lever through all positions:
R, N, D and pause for a few seconds in each position.
Return selector to PARK position. Let engine idle for 2
minutes. Wipe dipstick clean. Insert dipstick into filler
opening and withdraw. Measure distance from tip to fluid
level on dipstick. Compare to chart.

The factory service manual indicates to use a scan tool and
read the transmission fluid temperature from the tool. You
do not have access to such information so use this work around.

Hopefully your van has an outside temperature display somewhere
on the overhead console or in the instrument panel. Check the fluid
level first thing in the morning before you start your days activities.
Start the engine and note the outside temperature display. Use that
reading in the chart to determine fluid level. Follow the procedure
and measure.

If the vehicle has been sitting and not operated for several hours, fluid
drains and returns to the pan. You will get an excessively high reading
(you indicated 70 mm) but that is misleading. Fluid level must be
checked with engine running and is temperature dependent. Aim to
get the fluid level exactly between the minimum and maximum level.
Do not overfill.
This can cause foaming and excessive heat buildup
and is detrimental to transmission longevity

Do not get in a hurry with checking and adding fluid if it seems low. Add a little
fluid and then perform the procedure again tomorrow morning. When the
fluid is cold / cool it is very easy to panic and think it is too and add too much.
Several iterations over a number of days will get it set correctly.

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. . . .i still have an chime that comes on as soon as i turn power on but, i will address that next. i want to take care of the tranny first and foremost. You are awesome. . . .
On Chrysler vehicles, you will get a repeating chime for 5 - 6 second when ignition is first turned to ON / RUN and the driver side seat belt is not latched. The chime stops when you fasten the seat belt or the 5 - 6 second interval passes. After this and you put the vehicle into motion and the BCM (body control module) senses that any door or lift gate is not closed properly, a chime will sound. If this happens you would have a door ajar icon lamp illuminated on the instrument panel. If none of these preceding situations occurs or has been corrected and you still get a single chime sound, that is usually a signal that there are active diagnostic codes in the PCM (check engine lamp may or may NOT be illuminated). And if a pending diagnostic code has happened and is on its way to maturation as an active code, a single chime will sound. So let's get all the diagnostic code conditions remedied and removed, and this single chime sound should disappear.

. . . . One thing i have failed to mention, the three times that i myself have change the fluid and filter, i have not replaced the seal although i have it, i was afraid to damage something if i tried to get it out. it is in there tight. any ideas on this?
I believe you are referencing the seal that is recessed into the opening in the transmission that the nipple on the filter assembly inserts. You are wise in not forcing the situation. The transmission case is aluminum which is soft metal and can be gouged. Use a pick type tool (similar to the instrument a dentist uses to scrape tartar from teeth) to remove the seal. Here is a link to such a tool.

Performance Tool W942 - Hook/Pic Set | O'Reilly Auto Parts (at )

. . . On your chart you indicate temp, that is engine temp and at 82 is at 80mm with engine temp ay 212 then it should be closer to 50mm. i say it is overfilled but a quart ? 2 quarts?
The numbers I posted tend to run together and make it difficult to read.
At 70 Deg F temperature, minimum level is 3 mm; max level is 14 mm.
At 80 Deg F temperature, min level is 4 mm; max level is 19 mm.
At 200 Deg F temperature, min level is 40 mm; max level is 54 mm.

The temperature used in the chart is transmission fluid temperature; NOT engine temperature. At 212 deg F engine temperature, fluid temperature should be 180 - 190. 200+ degree transmission fluid temperature is too high and leads to fluid degradation and internal seal damage.

So if you are following the procedure exactly to the letter, letting the vehicle sit overnight so that engine and transmission temperature cool and reach ambient / outside / surrounding air temperature. Then you start the engine, move selector through all positions (P, R, N, D) and then let it idle for 2 minutes. I believe the transmission is overfilled! It is probably overfilled by 1 to 1.5 quarts.

Remove some of the fluid through the fluid fill tube. There are hand held vacuum devices for fluid extraction. A simpler, less expensive solution is available. If you have a turkey baster in the kitchen dedicate it to automotive duty. (Please buy a NEW one for kitchen service!) Go to a home improvement center such as Lowes, Home Depot or Ace Hardware and buy clear vinyl tubing, 1 foot length, in the appropriate size to fit the end of the turkey baster. Insert the baster with extension vinyl into the dipstick tube. Suction excess fluid and measure. Extract about 1.5 quarts.

Follow the procedure for checking fluid level with cold engine and vehicle at ambient / surrounding temperature. Your fluid level reading at 80 deg F fluid temperature (not engine temperature) should be between 4mm and 19 mm so I would adjust to get a level at 10 - 11 mm.

It is difficult to get an exact fluid temperature unless you can use a sophisticated scan tool that gives this information. Some DIY scan tools ($100 - $500 price range) may provide this information. So if you do not have the particular equipment to retrieve transmission fluid temperature from vehicle, how can you improvise?

A digital home thermometer with flexible probe might work. You clean the underneath side of the transmission pan, tape the probe to the pan and then activate the thermometer and read the temperature. You would need to leave the probe attached for 10 - 20 minutes to get an accurate reading. Of course the thermometer needs to have an upper range of at least 210 - 220 deg F to give correct information. If you have the old style, glass tube mercury thermometer for home health, do NOT use such a device. Those thermometers only had an upper range of 120 - 130 deg F and higher temperatures applied to the sensing bulb will cause the glass tube to crack and spill mercury.

Here is a link to a video that shows how to drain fluid, change filter and fill and check fluid on a Chrysler 62TE automatic transaxle. Of particular interest is the information and pictures presented at time interval 6:10 and beyond. Also the presenter shows actual levels on a dipstick and at interval 7:50 a picture of the chart.

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