Test Procedure
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
- DJ1 DTCS P0537 AND P0538: CHECK FOR SELF-TEST DTCS
Are any of the following DTCs present during PCM or TCM self-test: P0537 or P0538?
Yes No For KOEO and KOER DTC P0537, GO to DJ6.
For KOEO and KOER DTC P0538, GO to DJ2.
For continuous memory DTCs P0537 or P0538, GO to DJ9.Unable to duplicate or identify the fault at this time.
The concern is elsewhere. RETURN to SYMPTOM CHARTS for further direction. - DJ2 KOEO AND KOER DTC P0538: SIMULATE AN OPPOSITE SIGNAL TO THE PCM
- Key in OFF position.
- ACET Sensor connector disconnected.
- Connect a 5 amp fused jumper wire between the following:
Point A ACET Sensor Connector, Harness Side Point B ACET Sensor Connector, Harness Side ACET - Pin 1 SIGRTN - Pin 2 - Key ON, engine OFF.
- Carry out the self-test.
Is DTC P0537 present?
Yes No INSTALL a new ACET sensor. Key in OFF position.
GO to DJ3. - DJ3 CHECK THE ACET & SIGRTN CIRCUIT FOR AN OPEN IN THE HARNESS
- Remove the jumper wire(s).
- PCM connector disconnected.
- Measure the resistance between:
( + ) ACET Sensor Connector, Harness Side ( - ) PCM Connector, Harness Side ACET - Pin 1 ACET - Pin B1 SIGRTN - Pin 2 SIGRTN-C - Pin B41
Are the resistances less than 5 ohms?
Yes No GO to DJ4. REPAIR the open circuit. - DJ4 CHECK THE ACET CIRCUIT FOR A SHORT TO VREF IN THE HARNESS
- Key in OFF position.
- PCM connector disconnected.
- Measure the resistance between:
( + ) PCM Connector, Harness Side ( - ) PCM Connector, Harness Side ACET - Pin B1 VREF - Pin E40
Is the resistance greater than 10K ohms?
Yes No GO to DJ5. REPAIR the short circuit to VREF. - DJ5 CHECK THE ACET CIRCUIT FOR A SHORT TO VPWR IN THE HARNESS
- Key ON, engine OFF.
- Measure the voltage between:
( + ) ACET Sensor Connector, Harness Side ( - ) ACET - Pin 1 Ground
Is the voltage greater than 1 V?
Yes No REPAIR the short circuit to PWR. INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . - DJ6 KOEO AND KOER DTC P0537: SIMULATE AN OPPOSITE SIGNAL TO THE PCM
- ACET Sensor connector disconnected.
- Carry out the self-test.
Is DTC P0538 present?
Yes No INSTALL a new ACET sensor. GO to DJ7. - DJ7 CHECK THE ACET CIRCUIT FOR A SHORT TO SIGRTN IN THE HARNESS
- PCM connector disconnected.
- Measure the resistance between:
( + ) ACET Sensor Connector, Harness Side ( - ) ACET Sensor Connector, Harness Side ACET - Pin 1 SIGRTN - Pin 2
Is the resistance greater than 10K ohms?
Yes No GO to DJ8. REPAIR the short circuit. - DJ8 CHECK THE ACET CIRCUIT FOR A SHORT TO GND IN THE HARNESS
Is the resistance greater than 10K ohms?
Yes No INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . REPAIR the short circuit. - DJ9 CONTINUOUS MEMORY DTCS P0537 OR P0538: CHECK THE ACET & SIGRTN CIRCUIT FOR AN INTERMITTENT CONCERN
- ACET Sensor connector disconnected.
- Measure the voltage between:
( + ) ACET Sensor Connector, Harness Side ( - ) ACET Sensor Connector, Harness Side ACET - Pin 1 SIGRTN - Pin 2 - Key ON, engine OFF.
- While monitoring the voltage reading on the DMM, carry out the following (The voltage should be between 4.5 and 5.5 volts. The voltage reading will change suddenly when a fault is detected. For P0537, a sudden change could indicate a short to ground. For P0538, a sudden change could indicate an open ACET or SIGRTN circuit).
- Wiggle, shake, and bend small sections of the wiring harness while working from the sensor to the PCM.
- Key in OFF position.
- Inspect connectors for signs of damage, water ingress, corrosion, etc.
Is there any change in the voltage reading, or is a concern found?
Yes No ISOLATE the fault Unable to duplicate or identify the fault at this time. REPAIR as necessary. GO to Pinpoint Test Z .