DTC P0538


DTC P0538	Evaporator temperature sensor circuit high input
DETECTION CONDITION	• The PCM monitors the input voltage from the evaporator temperature sensor. If the input voltage at PCM terminal 1AD is 4.94 V or more, the PCM determines that the evaporator temperature sensor circuit has a malfunction.
POSSIBLE CAUSE	• Evaporator temperature sensor malfunction • Open circuit between evaporator temperature sensor terminal B and PCM terminal 1AD • Short to power circuit between evaporator temperature sensor terminal B and PCM terminal 1AD • Open circuit between evaporator temperature sensor terminal A and PCM terminal 1N • Poor connection at evaporator temperature sensor or PCM connector • PCM malfunction


STEP	INSPECTION		ACTION
1	PERFORM DTC CONFIRMATION PROCEDURE • Perform the DTC CONFIRMATION PROCEDURE. (See DTC CONFIRMATION PROCEDURE.) • Is the same DTC present?	Yes	Go to the next step.
1		No	Intermittent concern exists. Go to the INTERMITTENT CONCERN TROUBLESHOOTING procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING.)
2	INSPECT EVAPORATOR TEMPERATURE SENSOR FOR POOR CONNECTION • Turn the ignition switch off. • Disconnect the evaporator temperature sensor connector. • Inspect for poor connection (such as damaged, pulled-out pins, and corrosion). • Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 8.
2		No	Go to the next step.
3	CLASSIFY EVAPORATOR TEMPERATURE SENSOR MALFUNCTION OR WIRING HARNESS MALFUNCTION • Connect the WDS or equivalent to the DLC-2. • Access the A/CT V PID. • Connect a jumper wire between the evaporator temperature sensor terminals (wiring harness-side) A and B. • Verify the A/CT V value. • Is the voltage 4.9 V or less?	Yes	Replace the evaporator temperature sensor, then go to Step 8.
3		No	Go to the next step.
4	INSPECT EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR SHORT TO POWER • Turn the ignition switch to the ON position. (Engine off). • Measure the voltage between evaporator temperature sensor terminal B (wiring harness-side) and body ground. • Is the voltage B+?	Yes	Repair or replace the wiring harness for short to power, then go to Step 8.
4		No	Go to the next step.
5	INSPECT PCM FOR POOR CONNECTION • Turn the ignition switch off. • Disconnect the PCM connector. • Inspect PCM terminals 1AD and 1N (wiring harness-side) for tightness using a feeler tool. • Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 9.
5		No	Go to the next step.
6	INSPECT EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR OPEN CIRCUIT • Inspect continuity between evaporator temperature sensor terminal B (wiring harness-side) and PCM terminal 1AD (wiring harness-side). • Is there continuity?	Yes	Go to the next step.
6		No	Repair or replace the wiring harness for an open circuit, then go to Step 9.
7	INSPECT IAT SENSOR GROUND CIRCUIT FOR OPEN CIRCUIT • Inspect for continuity between evaporator temperature sensor terminal A (wiring harness-side) and PCM terminal 1N (wiring harness-side). • Is there continuity?	Yes	Go to the next step.
7		No	Repair or replace the wiring harness for an open circuit, then go to the next step.
8	VERIFY TROUBLESHOOTING OF DTC P0538 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the WDS or equivalent. • Perform the KOEO/KOER self-test. (See KOEO/KOER SELF-TEST.) • Is the same DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION.)
8		No	Go to the next step.
9	VERIFY AFTER REPAIR PROCEDURE • Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE.) • Are any DTCs present?	Yes	Go to the applicable DTC troubleshooting. (See DTC TABLE.)
9		No	Troubleshooting completed.