Test DJ: Air Conditioning Evaporator Temperature Sensor: Testing
- 1) For KOEO & KOER Only DTCs P0538 & P1437: Simulate Opposite Signal To PCM
DTC P0538 or P1437 is set when ACET signal is more than self-test maximum of 4.5 volts. Possible causes for this fault are:- ACET Circuit Open Or Shorted To VREF
- SIG RTN Circuit Open To ACET Sensor
- Faulty ACET Sensor
- Faulty Powertrain Control Module (PCM)
Disconnect ACET sensor connector. Connect a jumper wire between ACET and SIG RTN circuits at ACET sensor harness connector. See Figure or Figure . Repeat KOEO or KOER self-test where DTC P0538 or P1437 was received.
If DTC P0537 or P1436 is received during self-test, replace ACET sensor. If DTC P0537 or P1436 is not received during self-test, turn ignition switch to OFF position, remove jumper wire and go to next step.
- 2) Check ACET & SIG RTN Circuits For Open In Harness
Disconnect PCM connector(s). Using a DVOM, measure resistance of ACET and SIG RTN circuits between PCM harness connector and ACET sensor harness connector. If both resistance measurements are less than 5 ohms, replace PCM. If either resistance measurement is 5 ohms or more, repair open in affected circuit.NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 2) to step 4). No test procedures have been omitted. - 4) Check ACET Circuit For Short To VREF In Harness
Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance between ACET and VREF circuits at PCM harness connector. If resistance measurement is more than 10 k/ohms, replace PCM. If resistance is 10 k/ohms or less, repair short between ACET and VREF circuits. - 5) For KOEO & KOER Only DTCs P0537 & P1436: Simulate Opposite Signal To PCM
DTC P0537 or P1436 is set when ACET signal is less than self-test minimum of .13 volt. Possible causes for this fault are:- ACET Circuit Shorted To GND Or SIG RTN
- Faulty ACET Sensor
- Faulty Powertrain Control Module (PCM)
Disconnect ACET sensor connector. Repeat KOEO or KOER self-test where DTC P0538 or P1437 was received. If DTC P0538 or P1437 is received, replace ACET sensor. If DTC P0538 or P1437 is not received, go to next step.
- 6) Check ACET Circuit For Short To Ground In Harness
Disconnect PCM connector(s). Using a DVOM, measure resistance between ACET and SIG RTN circuits at ACET sensor harness connector. Also, measure resistance between ACET circuit at ACET sensor harness connector and ground. If both resistance measurements are more than 10 k/ohms, replace PCM. If either resistance measurement is 10 k/ohms or less, repair short in affected circuit.NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 6) to step 10). No test procedures have been omitted. - 10) For Continuous Memory Only DTCs P0537, P0538, P1436 & P1437: Check ACET & SIG RTN Circuits For Intermittent Concerns
Disconnect ACET sensor connector. Using a DVOM, measure voltage between ACET and SIG RTN circuits at ACET sensor harness connector. Turn ignition switch to ON position. While monitoring voltage reading on DVOM, shake, wiggle and bend small sections of wiring harness while working toward PCM. Voltage should be a constant 4.5-5.5 volts. Voltage reading will change suddenly when a fault is detected.Turn ignition switch to OFF position. Inspect associated connectors for damage. If there is any change in voltage reading, or if a concern is found, isolate fault and repair as necessary. If no faults are indicated, concern is intermittent and cannot be identified at this time. Go to TEST Z, step 1) .