Allpar Forums banner
1 - 8 of 8 Posts

·
Registered
Joined
·
5,052 Posts
Discussion Starter · #1 ·
I don't know if it is just coinicidence but I have been struggling with getting cooling system flushed on a 2016 Jeep Patriot with 2.4 liter engine and 6 speed Hyundai transmission. Finally completed flush and job successful with no leaks and no air pockets in the system.

But now the left front turn signal and park lamp and side marker lamp do not work. In addition engine at start up bucks and jerks. Malfunction indication lamp illuminated and 1 code present: U0401 -- implausible data from PCM. I had to remove the front fascia to gain access to radiator drain plug and reintalled. In the process did I disrupt wiring or just a coincidence?

I have checked a wiring diagram and find that the left front park, turn, side marker lamp assembly shares a common ground G102. This same ground is shared by circuitry within the TIPM. I am thinking that something has compromised ground G102 and this is coincidenttally causing the lighting problems and engine running issues. Fix the poor ground at G102 and issues resolved.

Problem is that I cannot find ground G102. Wiring diagram I have reviewed says it is on topside of transmission. I have removed the batery and battery tray but do not see a group of ring eyelets stacked and bolted to the transmission. I wonder if the diagram is correct? If anyone has a more detailed of ground G102 and where to find it I would appreciate it.

See attached image that shows commonality of G102.

Product Font Schematic Engineering Parallel
 

·
Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
Joined
·
22,674 Posts
The 2014 may be different than the 2016.
It is called G906A instead of G102.
I would rinse the top of the transaxle and battery tray with an alkaline, like baking soda.

Rectangle Parallel Slope Font Pattern



Tire Wheel Automotive lighting Automotive tire Automotive design
 

·
Registered
Joined
·
5,052 Posts
Discussion Starter · #3 ·
. . .
The 2014 may be different than the 2016.
It is called G906A instead of G102.
I would rinse the top of the transaxle and battery tray with an alkaline, like baking soda. . . .
Always a possibility that vehicle wiring changes occur from year to year. I will look in the area under the TIPM.

Cleaning the top of the transaxles seems the next course of action. I am going to remove the 2 connectors on topside which are the wiring ports for the electro hydraulic control assembly. Foreign substances either dry or liquid could be a source of miscommunication with the TCM.

Thanks I C !
 

·
Registered
Joined
·
5,052 Posts
Discussion Starter · #4 · (Edited)
. . . Always a possibility that vehicle wiring changes occur from year to year. I will look in the area under the TIPM.

Cleaning the top of the transaxles seems the next course of action. I am going to remove the 2 connectors on topside which are the wiring ports for the electro hydraulic control assembly. Foreign substances either dry or liquid could be a source of miscommunication with the TCM. . . .
I could not find the grouond G906a on my vehicle. No ground eyelets under or in the vicinitry of the TIPM.

I discovered the issue I had with the left front park, turn, side marker lamp. When reinstalling the front fascia I forgot to attach the electrical connetor for this assembly to its socket. Very embarrassing mistake ! Reattached and left front turn signal and parking lamp now function properly.

So that narrows focus to a more serious problem. I thought the sudden bucking and jerking was a result of system cooling flush caused a water problem in an electrical connectioni. Now I am convinced there is a more serious issue.

Engine bucks and jerks, very little power. traction control, electronic throttle and engine malfunction lamp illuminated. Only code that I was able to retrieve is U0401 - IMPLAUSIBLE DATA RECEIVED FROM ECM-PCM.

I am using an ACtron 9180 scan tool. I tried clearing the code U0401 but the tool indicated that the ignitiion key was not in the ON / RUN position. But I know the 16 pin connector is securely attached in its receptacle as I was able to retrieve the code. So that might be another indication of a network CAN bus failure???

I am wondering if this code U0401 is a symptom and the actual issue is another component that has failed and is not sending proper electrical signal to the PCM? Would a failed throttle body motor cause this issue???
 

·
Super Moderator
Joined
·
32,801 Posts
Could be one of two things causing this, from this latest info.
1) Bad ignition switch making intermittent contact, so that engine cuts out randomly. I'd expect that to be all the time, not just at startup.
2) Battery and/or charging system failing. When my 8-yr old original battery failed, the battery light did come on, but it was also jerking, and ESC and other warning lights came on, and transmission was shifting back and forth, jerking into gears not appropriate for the speed. I made it about 10 miles in this condition before it outright died.
If you have the original battery, it may be dying now.

These cars do have a problem with the throttle body's stepper motor gears stripping - they are plastic. But they trip fault codes that indicate TB problems, in addition to ESC and throttle lights coming on. So unless you get codes like P2101 and P2128, I would not expect the throttle body to be the problem. My wife had that fail, and at first it was lagging throttle performance, with these codes. Within a few days it jerked and stalled out altogether. Had to replace the throttle body with a redesigned Mopar one with a different motor that required rewiring the car's harness (Chrysler supplied the parts and instructions with the throttle body).
 

·
Registered
Joined
·
5,052 Posts
Discussion Starter · #6 ·
. . .
1) Bad ignition switch making intermittent contact, so that engine cuts out randomly. I'd expect that to be all the time, not just at startup. . . .
When you turn the ignition key switch to the ON / RUN position, a low voltage signal is sent on a multiplexed circuit from the ignition switch to the TIPM. The TIPM interprets the signal and closes the control circuit to the RUN relay. So the ignition RUN circuit function is not directly controlled from the key switch as in years past. So I do not think that is the issue.

. . . .2) Battery and/or charging system failing. When my 8-yr old original battery failed, the battery light did come on, but it was also jerking, and ESC and other warning lights came on, and transmission was shifting back and forth, jerking into gears not appropriate for the speed. I made it about 10 miles in this condition before it outright died.
If you have the original battery, it may be dying now. . . .
Battery is 5 years old and has sufficient charge to activate the starter and turn engine vigorously. Will have to check charging voltage to see if this is a possible issue.

. . . These cars do have a problem with the throttle body's stepper motor gears stripping - they are plastic. But they trip fault codes that indicate TB problems, in addition to ESC and throttle lights coming on. So unless you get codes like P2101 and P2128, I would not expect the throttle body to be the problem . . .
All possible diagnostic codes that pertain to electronic throttle body control and accelerator position control fall in the range P2100 - - - P2167. Vehicle displays no codes in that range so that would tend to make one think that there is no failure ot the stepper motor in the throttle body.

I am tempted to remove the inlet air plenum tube between the air filter housing and throttle body at the intake manifold. With ignition key ON the stepper motor should move. Unfortunately access is not easy as the throttle
body is mounted low on between the radiator fan assembly and engine block.

Code U0401 has me puzzled. Service manual description for the code indicates implausible data is received from the PCM / ECM. Service procedures go on to describe parity errors in the digital messages. But to me implausible data or illogical data would indicate NOT a parity error but the PCM is reading feedback data from the throttle body stepper motor that does not agree with other sensor data that the PCM is receiving. That would tend to point to circuit problems (high resistance, short to power, short to ground???) or a stuck stepper motor.

So can one believe the interpretation of code U0401? Sometimes diagnostic codes are a symptom of other electrical issues. This one will be difficult to diagnose correctly.

Thaks for the brain storming !
 

·
Registered
Joined
·
5,052 Posts
Discussion Starter · #7 ·
Does any have a detailed pinout diagram of the 2 electrical connects at the PCM for a 2016 Jeep Patriot with 2.4 liter 4 cylinder engine? I need to know the location of 2 pins in connector C1 or C2 which control the throttle body stepper motor. It appears each connector has 50+ pathways but not all are used.
 
1 - 8 of 8 Posts
Top