Jeep Cherokee Check Engine Light Codes.<\/p>\n
On the 91 to 96 Jeep Cherokees the ECU codes are accessible by watching the Check engine light blink on the dash. You cycle the key on and off three times leaving it on but not starting the Jeep. The codes will begin to flash on the dash light. Count the flashes and note the pause between flashes. For example the first code will usually be a 12. The light will blink once then pause and then blink twice more. The last code is always a 55.<\/p>\n
Below are the instructions from the FSM on how to get the codes. Below that is the chart of what the codes mean. This chart was taken from the 94 FSM but all the HO engines will be similar.<\/p>\n
ACCESSING DIAGNOSTIC TROUBLE CODES
\nA stored Diagnostic Trouble Code (DTC) can be displayed by cycling the ignition key On-Off-On-Off-On within three seconds and observing the Malfunction Indicator Lamp. This lamp was formerly referred to as the Check Engine Lamp. The lamp is located on the instrument panel.<\/p>\n
11\t*\tNo Crank Reference Signal at PCM\tNo crank reference signal detected during engine cranking.
\n12\t*\tBattery Disconnect\tDirect battery input to PCM was disconnected within the last 50 Key-on cycles.
\n13\t**\tNo Change in MAP From Start to Run\tNo difference recognized between the engine MAP reading and the barometric (atmospheric) pressure reading at start-up.
\n14\t**\tMAP Sensor Voltage\tMAP sensor input below minimum acceptable voltage.
\nor
\nMAP sensor input above maximum acceptable voltage.
\n15\t**\tNo Vehicle Speed Sensor Signal\tNo vehicle distance (speed) sensor signal detected during road load conditions.
\n17\t*\tEngine is Cold Too Long\tEngine coolant temperature remains below normal operating temperatures during vehicle travel (thermostat).
\n21\t**\tO2S Stays at Center\tNeither rich nor lean condition detected from the oxygen sensor input.
\nor
\nO2S Shorted to Voltage Oxygen sensor input voltage maintained above the normal operating range.
\n22\t**\tECT Sensor Voltage\tEngine coolant temperature sensor input above maximum acceptable voltage.
\nor
\nEngine coolant temperature sensor input below minimum acceptable voltage.
\n23\t**\tIntake Air Temp Sensor
\nVoltage\tLow Intake air temperature sensor input below the minimum acceptable voltage.
\nor
\nIntake air temperature sensor input above the maximum acceptable voltage.
\n24\t**\tThrottle Position Sensor
\nVoltage\tThrottle position sensor input above the maximum acceptable voltage.
\nor
\nThrottle position sensor input below the minimum acceptable voltage.
\n25\t**\tIdle Air Control Motor
\nCircuits\tA shorted condition detected in one or more of the idle air control motor circuits.
\n27\t*\tInjector Control Circuit\tInjector output driver does not respond properly to the control signal.
\n33\t*\tA\/C Clutch Relay Circuit\tAn open or shorted condition detected in the A\/C clutch relay circuit.
\n34\t*\tSpeed Control Solenoid
\nCircuits\tAn open or shorted condition detected in the Speed Control vacuum or vent solenoid circuits.
\nor
\nSpeed Control Switch Always Low
\nSpeed Control switch input below the minimum acceptable voltage.
\nor
\nSpeed Control Switch Always High
\nSpeed Control switch input above the maximum acceptable voltage
\n35\t*\tRad Fan Control Relay
\nCircuits\tAn open or shorted condition detected in the radiator fan relay circuit.<\/p>\n
41\t**\tGenerator Field Not
\nSwitching Properly\tAn open or shorted condition detected in the generator field control circuit
\n42\t*\tAuto Shutdown Relay
\nControl Circuit\tAn open or shorted condition detected in the auto shutdown relay circuit.
\n44\t*\tBattery Temp Sensor
\nVolts out of Limit\tAn open or shorted condition exists in the engine coolant temperature sensor circuit or a problem exists in the PCM\u2019s battery temperature voltage circuit.
\n46\t**\tCharging System Voltage
\nToo High\tBattery voltage sense input above target charging voltage during engine
\nOperation
\n47\t**\tCharging System Voltage
\nToo Low\tBattery voltage sense input below target charging during engine operation.
\nAlso, no significant change detected in battery voltage during active test of generator output.
\n51\t**\tO2S Signal Stays Below Center (Lean)\tOxygen sensor signal input indicates lean air\/fuel ratio condition during engine operation.
\n52\t**\tO2S Signal Stays Above Center (Rich)\tOxygen sensor signal input indicates rich air\/fuel ratio condition during
\nengine operation
\n53\t*\tInternal PCM Failure
\nOr
\nPCM Failure SPI Communications\tPCM Internal fault condition detected.
\nor
\nPCM Internal fault condition detected.
\n54\t*\tNo Cam Sync Signal at
\nPCM\tNo fuel sync (camshaft signal) detected during engine cranking.<\/p>\n
55\t\t. N\/A\tCompletion of diagnostic trouble code display on the Malfunction Indicator Lamp (Check Engine Lamp).
\n62\t*\tPCM Failure SPI miles not stored\tUnsuccessful attempt to update SPI miles in the PCM EEPROM.<\/p>\n
63\t*\tPCM Failure EEPROM
\nWrite Denied\tUnsuccessful attempt to write to an EEPROM location by the PCM.<\/p>\n
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded. Cycle Ignition key as described in manual and observe code flashed by Check Engine lamp.
\n** Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.<\/p>\n","protected":false},"excerpt":{"rendered":"
Jeep Cherokee Check Engine Light Codes. On the 91 to 96 Jeep Cherokees the ECU codes are accessible by watching the Check engine light blink on the dash. You cycle the key on and off three times leaving it on but not starting the Jeep. The codes will begin to flash on the dash light. … <\/p>\n