P1635

CIRCUIT DESCRIPTION
^ The engine control module (ECM) uses the 5-volt reference 1 circuit as a sensor feed to the following sensors:
- The accelerator pedal position (APP) sensor 1
- The APP sensor 3
- The fuel rail pressure (FRP) sensor
^ The ECM monitors the voltage on the 5-volt reference 1 circuit. If the voltage is out of tolerance, the ECM will set DTC P1635.

CONDITIONS FOR RUNNING THE DTC
The ignition is ON.

CONDITIONS FOR SETTING THE DTC
^ The ECM detects a voltage out of tolerance condition on the 5-volt reference A circuit.
^ The above condition is present for longer than 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Clear the MIL and the DTC with a scan tool.

TEST DESCRIPTION

DTC P1635 - Steps 1-4:

DTC P1635 - Steps 5-13:

The numbers below refer to the step numbers on the diagnostic table.
8. A short to the transmission control module (TCM) MIL request may not show up on the scan tool as skewed sensor readings. The TCM momentarily grounds the circuit as a test, and the test is just long enough to set this DTC.
11. This vehicle is equipped with a ECM which utilizes an electrically erasable programmable read only memory (EEPROM). When the ECM is being replaced, the new ECM must be programmed.