How to retrieve trouble codes from Jeep vehicles made before 1995. When you see a check engine light blink or stay on steady while you drive it means the computer has stored a diagnostic trouble code or codes. These codes are meant to help define a particular problem is the engine or emissions system.
Step 1 - Trouble codes are identified by a two digit code. To activate the code gathering sequence turn the ignition key on and off five times in rapid secession ending with the key in the on position. This will start the code gathering, by watching the check engine light and counting the number of times it flashes. The first set of flashes will be the first digit of the trouble code. There will be a short pause and then start flashing again, count the number and that will be the second digit in the trouble code. For example if the first blink number is four and the second number blink is six the code number is 46.
Step 2 - To restart the code gathering, turn the the ignition key to the off position and wait 5 minutes and start over. When the code gathering has been completed the system will flash a number fifty five which means the code display has ended. To clear codes after the repairs have been performed remove the negative battery cable and within two minutes and reconnect.
Trouble Code Table
11 No crank reference signal
12 Direct battery input to PCM was disconnected within the last 50 key-on cycles
13 No difference recognized between the engine MAP reading and the barometric (atmospheric) pressure reading at start-up
14 MAP sensor below minimum acceptable voltage
15 No vehicle speed sensor signal detected
17 Engine coolant temperature below normal operating temperatures
21 Neither rich nor lean condition detected from the oxygen sensor
22 Engine coolant temperature sensor input above maximum acceptable voltage
23 Intake manifold air temperature sensor input above maximum acceptable voltage
24 Throttle position sensor input above maximum acceptable voltage
25 A short condition detected in the idle air control motor
27 Injector output driver does not respond properly to the control signal or injector
33 An open or shorted condition detected in the A/C clutch relay circuit
34 An open or shorted condition detected in the speed control vacuum or vent solenoid circuits
35 An open or shorted condition detected in the radiator fan relay circuit
41 An open or shorted condition detected in the generator field control circuit
42 An open or shorted condition detected in the auto shutdown relay circuit
44 An open or shorted condition exists in the engine coolant temperature sensor circuit
46 Battery voltage sense input above target charging voltage during engine operation
47 Battery voltage sense input below target charging voltage during engine operation
51 Oxygen sensor signal input indicates lean air/fuel ratio condition during engine operation
52 Oxygen sensor signal input indicates rich air/fuel ratio condition during engine operation
53 PCM internal fault condition detected
54 No fuel sync (camshaft signal) detected during engine cranking
55 Completion of diagnostic trouble code display on the malfunction indicator lamp (check engine lamp)
62 Unsuccessful attempt to update SRI (service reminder indicator) miles in the PCM EEPROM
63 Unsuccessful attempt to write to an EEPROM location by the PCM
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