P1635

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
The PCM uses a common 5.0 Volt Reference 1 circuit as a sensor feed. This circuit supplies 5 Volts to the following sensors:
- The A/C Pressure sensor.
- The MAP sensor.
- The EGR valve.

The PCM monitors the voltage on the 5.0 Volt Reference 1 circuit. This DTC sets if the voltage is out of range.

CONDITIONS FOR RUNNING THE DTC
The ignition switch is in the RUN position.

CONDITIONS FOR SETTING THE DTC
- The 5.0 volt reference circuit is out of range.
- All above conditions are present for greater than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The PCM illuminates the Malfunction Indicator Lamp on the second consecutive drive trip that the diagnostic runs and fails.
- The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive drive trip, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The PCM turns the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.
- A last test failed (current DTC) clears when the diagnostic runs and does not fail.
- A History DTC clears after forty consecutive warm.up cycles, if this or any other emission related diagnostic does not report any failures.
- The PCM battery voltage is interrupted.
- Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS
Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed. temperature etc.) that you observed. This will isolate when the DTC failed. For an intermittent condition, refer to Symptoms. Testing and Inspection

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. The 5.0 volt reference circuits for the sensors listed are tied together inside the PCM. This step separates the 5.0 volt reference circuits and isolates the 5.0 volt reference circuit which is shorted to voltage.
3. The 5.0 volt reference circuits for the sensors listed are tied together inside the PCM. This step separates the 5.0 volt reference circuits and isolates the 5.0 volt reference circuit which is shorted to ground.
4. This step isolates the 5.0 volt reference circuit from the sensor signal circuit.