Chrysler, Plymouth, and Dodge Computer Codes
Chrysler Corporation (including Dodge and Plymouth) vehicles with fuel injection, like all current computer-controlled vehicles, watch their own behavior and set "error codes" when they see something which is not as it should be. Computers only do what you tell them, so they might not see problems which do exist, or they might see problems that do not exist, or they might indicate a problem which is in reality caused by some other component. They work is by checking their inputs against each other - for example, if the voltage coming from the oxygen sensor is not what it expects given where the throttle is, how fast the engine is moving, etc., it will post an error code and, in some cases, light up a warning lamp on the instrument panel.
Dealers have sophisticated computers which plug into your car's computer and can gain massive amounts of information; but backyard mechanics can also benefit from knowing what the computer thinks is wrong (since it's often right), especially given that those well-equipped dealers often have dishonest and poorly-trained mechanics.
Please read all the bullets before zooming to the codes. Thanks.
- When the computer indicates major failure, it can activate Limp In mode, which guesses about data to compensate for sensor failure, allowing you to get the car to a mechanic. One major symptom of this is the transmission sticking in second gear. This is a feature!
- A loose gas cap may light up the Check Engine light! (Thanks, Lyn Clark)
On older cars (1980s-1990s)
Late-1990s and newer cars
You may want to invest in an OBD compatible code reader. They're inexpensive and some can record sensor readings and save them to a file, making diagnosis easier. This is the code list. That said, many Chrysler cars, vans, and trucks will show you codes without any readers.
- Codes are displayed on the odometer.
- On some cars, the codes will read out if the engine light is on - all you have to do is put the key into the RUN position.
- Normally, to get codes, you put the key on OFF and then rapidly do OFF-ON-OFF-ON-OFF-ON (on some cars you have to do four or five, not three, OFF-ON cycles). On our test 2002 car, the key did not go back to unlock, so it was ACC-ON-ACC-ON-ACC-ON. You may have to set the parking brake first (Thanks, Steven Midway)
- 1998-2002 (maybe more) Dodge trucks and Jeeps, put transmission in neutral, parking brake on, then do the acc-run key sequence 3 times ending with RUN.
- Dan Stewart wrote about the 1999+ Voyager/Caravan:
- Get Diagnostic Trouble Codes by placing the key into the ignition. Push and hold the both the "Trip" and the "Reset" buttons with the left hand and turn the key to the "ACC" position (first position between "LOCK" and "RUN"). Continue to hold both buttons in and count to 5. Release both buttons, display should read trip mileage instead of total mileage. Push the "TRIP" button and the odometer will display DTC'S in rotating sequence instead of displaying total mileage.
Resetting the computer
The computer will eventually reset itself; you can also use a scan tool. (See our transmission repair page for information on resetting the computer's transmission information.) Disconnecting the battery for a few minutes resets the computer, but loses clock and other settings.
Sid Willoughby wrote: “To clear the check engine light on a 2002 Dodge Ram once the problem is resolved. Start the engine and drive forward then in reverse (you only have to move the truck a few feet in each direction) the turn the ignition off. Do this sequence three times. When you start the vehicle the fourth time the check engine light should go out.” (This procedure may work on other vehicles.)
The code lists
- A common code now is P0513 - as far as we know, it just means the theft prevention system misread the Sentry Key radio code in your key (or that you put the wrong key in the ignition!). These keys were used starting in 1998.
- P-style computer error codes (late 1990s and newer), which apply to vehicles made in the late 1990s and in the 2000s.
- Climate control error codes
- 1980s-1990s codes. You can find out by trial and error which list is right for you. The older codes were two digits; the newer codes start with a P and have more digits.