[Wheelin98TJ]

If your TJ has a check engine light illuminated, below is the procedure for retrieving the diagnostic trouble code(s):

1. Turn the ignition key until the digital odometer displays, then turn it back to off. Repeat three times in succession. (ON/OFF/ON/OFF/ON)
2. Count the number of times the check engine light on the dash flashes on and off. The number of flashes represents the trouble code. There is a slight pause between the flashes representing the first and second digits of the code. Longer pauses separate different trouble codes.
3. For example, light flashes 5 times, then a short pause, then flashes 5 more times. This is code 55.
4. Diagnostic trouble codes will also be shown in the odometer display.
5. Code 55 is the last diagnostic trouble code displayed.
6. See below for list of diagnostic trouble codes.

Note: This procedure does not work on 1998, 1999, and some 2000 model TJs.


Thanks to Knuckelhead for pointing out that it does not work on some 2000 models.

[Wheelin98TJ]

Below are the two digit diagnostic trouble codes:

[Wheelin98TJ]

Below are the 4 digit codes that begin with P:

[Wheelin98TJ]

4 digit codes that begin with P continued:

[Wheelin98TJ]

4 digit codes that begin with P continued:

[FernBchJeep]

Below are the U-codes as well.


U0001 CAN C BUS
U0001 CAN C BUS
U0001 CAN C BUS CIRCUIT
U0002 CAN C BUS OFF PERFORMANCE
U0010 CAN INTERIOR BUS
U0010 CAN INTERIOR BUS
U0011 CAN INTERIOR BUS OFF PERFORMANCE
U0019 CAN INTERIOR BUS(+)/(-) CIRCUIT
U0020 CAN INTERIOR BUS OFF PERFORMANCE
U0100 LOST COMMUNICATION WITH ECM/PCM
U0100 LOST COMMUNICATION WITH ECM/PCM
U0100 LOST COMMUNICATION WITH ECM/PCM
U0100 LOST COMMUNICATION WITH ECM/PCM
U0101 LOST COMMUNICATION WITH TCM
U0101 LOST COMMUNICATION WITH TCM
U0101 LOST COMMUNICATION WITH TCM
U0114 LOST COMMUNICATION WITH FINAL DRIVE CONTROL MODULE
U0114 LOST COMMUNICATION WITH FINAL DRIVE CONTROL MODULE
U0121 LOST COMMUNICATION WITH ABS
U0121 LOST COMMUNICATION WITH ANTI-LOCK BRAKE MODULE
U0121 LOST COMMUNICATION WITH ANTI-LOCK BRAKE SYSTEM (ABS) CONTROL MODULE
U0121 LOST COMMUNICATION WITH ANTI-LOCK BRAKE MODULE
U0121 LOST COMMUNICATION WITH ANTI-LOCK BRAKE MODULE
U0121 LOST COMMUNICATION WITH ANTI-LOCK BRAKE MODULE
U0126 LOST COMMUNICATION WITH SAS - CAN C (STEERING ANGLE SENSOR)
U0141 LOST COMMUNICATION WITH FCM
U0141 LOST COMMUNICATION WITH FRONT CONTROL MODULE (TIPM)
U0141 LOST COMMUNICATION WITH FRONT CONTROL MODULE
U0141 LOST COMMUNICATION WITH FRONT CONTROL MODULE
U0141 LOST COMMUNICATION WITH FRONT CONTROL MODULE (TIPM)
U0141 LOST COMMUNICATION WITH FRONT CONTROL MODULE (TIPM)
U0141 LOST COMMUNICATION WITH FRONT CONTROL MODULE
U0146 LOST COMMUNICATION WITH CENTRAL GATEWAY
U0151 LOST COMMUNICATION WITH OCCUPANT RESTRAINT CONTROLLER (ORC)
U0151 LOST COMMUNICATION WITH OCCUPANT RESTRAINT CONTROLLER
U0151 LOST COMMUNICATION WITH OCCUPANT RESTRAINT CONTROLLER (ORC)
U0151 LOST COMMUNICATION WITH OCCUPANT RESTRAINT CONTROLLER
U0154 LOST COMMUNICATION WITH OCCUPANT CLASSIFICATION MODULE
U0154 LOST COMMUNICATION WITH OCCUPANT CLASSIFICATION MODULE
U0154 LOST COMMUNICATION WITH OCCUPANT CLASSIFICATION MODULE
U0154 LOST COMMUNICATION WITH OCCUPANT CLASSIFICATION MODULE
U0155 LOST COMMUNICATION WITH CLUSTER/CCN
U0155 LOST COMMUNICATION WITH CLUSTER/CCN (SKREEM)
U0155 LOST COMMUNICATION WITH CLUSTER/CCN
U0155 LOST COMMUNICATION WITH CLUSTER/CCN
U0155 LOST COMMUNICATION WITH CLUSTER/CCN
U0161 LOST COMMUNICATION WITH COMPASS MODULE
U0164 LOST COMMUNICATION WITH HVAC CONTROL MODULE
U0164 LOST COMMUNICATION WITH HVAC CONTROL MODULE
U0167 LOST COMMUNICATION WITH INTRUSION TRANSCEIVER CONTROL MODULE
U0167 LOST COMMUNICATION WITH INTRUSION TRANSCEIVER CONTROL MODULE
U0168 LOST COMMUNICATION WITH VEHICLE SECURITY CONTROL MODULE (SKREEM-WCM)
U0168 LOST COMMUNICATION WITH VEHICLE SECURITY CONTROL MODULE (SKREEM/WCM)
U0168 LOST COMMUNICATION WITH VEHICLE SECURITY CONTROL MODULE (SKREEM/WCM)
U0168 LOST COMMUNICATION WITH VEHICLE SECURITY CONTROL MODULE (SKREEM/WCM)
U0170 LOST COMMUNICATION W/UP-FRONT LEFT SATELLITE ACCELERATION SENSOR
U0171 LOST COMMUNICATION W/UP-FRONT RIGHT SATELLITE ACCELERATION SENSOR
U0172 LOST COMMUNICATION W/LEFT SIDE SATELLITE ACCELERATION SENSOR 1
U0175 COMMUNICATION W/RIGHT SIDE SATELLITE ACCELERATION SENSOR 1
U0184 LOST COMMUNICATION WITH RADIO
U0184 LOST COMMUNICATION WITH RADIO
U0184 LOST COMMUNICATION WITH RADIO
U0184 LOST COMMUNICATION WITH RADIO
U0184 LOST COMMUNICATION WITH RADIO
U0186 LOST COMMUNICATION WITH AUDIO AMPLIFIER
U0186 LOST COMMUNICATION WITH AUDIO AMPLIFIER
U0186 LOST COMMUNICATION WITH AUDIO AMPLIFIER
U0186 LOST COMMUNICATION WITH AUDIO AMPLIFIER
U0193 LOST COMMUNICATION WITH TRAFFIC INFORMATION RECEIVER MODULE
U0195 LOST COMMUNICATION WITH SDARS
U0195 LOST COMMUNICATION WITH SDAR
U0197 LOST COMMUNICATION WITH HANDS FREE PHONE MODULE
U0197 LOST COMMUNICATION WITH HANDS FREE MODULE
U0199 LOST COMMUNICATION WITH DRIVERS DOOR MODULE
U0200 LOST COMMUNICATION WITH PASSENGER DOOR MODULE
U0415 IMPLAUSIBLE DATA RECEIVED FROM ABS
U0447 IMPLAUSIBLE DATA RECEIVED FROM CENTRAL
U1008 LIN 1 BUS
U1008 LIN 1 BUS
U110A LOST COMMUNICATION WITH SCM
U110C LOST FUEL LEVEL MESSAGE
U110D LOST COMMUNICATION WITH SECURITY SIREN
U110E LOST AMBIENT TEMPERATURE MESSAGE
U110F LOST FUEL VOLUME MESSAGE
U1110 LOST VEHICLE SPEED MESSAGE
U1113 LOST A/C PRESSURE MESSAGE
U1120 LOST WHEEL DISTANCE MESSAGE
U113B LOST COMMUNICATION WITH SWITCH BANK MODULE
U1149 LOST COMMUNICATION WITH MULTIFUNCTION
U1159 LOST COMMUNICATION WITH ASBS
U1169 LOST COMMUNICATION WITH INTRUSION SENSOR 1
U1170 LOST COMMUNICATION WITH INTRUSION SENSOR 2
U1179 LOST COMMUNICATION WITH INTRUSION SENSOR 3

[FernBchJeep]

U1403 Implausible Fuel Level Signal Received
U1411 Implausible Fuel Volume Signal Received
U1412 Implausible Vehicle Speed Signal Received
U1414 Implausible/missing Ecu Network Configuration Data
U1415 Implausible/missing Vehicle Configuration Data
U1416 Implausible Security Siren Signal Received
U1417 Implausible Left Wheel Distance Signal Received
U1418 Implausible Right Wheel Distance Signal
U1419 Implausible Data Received From Ocs Sensor 3 - Left Front
U141a Implausible Data Received From Ocs Sensor 2 - Right Front
U141b Implausible Data Received From Ocs Sensor 4 - Left Rear
U141c Implausible Data Received From Ocs Sensor 1 - Right Rear