GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0652: 5-Volt Reference 2 Circuit Low Voltage

DTC P0653: 5-Volt Reference 2 Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

CKP Sensor 5-Volt Reference

P0652, P0335, P2127

P0335

P0335

P0335, P0653, P2128

--

APP Sensor 2 - 5-Volt Reference

P0335, P0652, P2127

P2138

P2127

P0653, P2128

--

Circuit/System Description

The engine control module (ECM) supplies 5 volts to components through 5-volt reference circuits. These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together in three reference groups inside the ECM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect multiple components. The ECM monitors voltage on the 5-volt reference circuits.

Conditions for Running the DTC

P0652

    • DTC P0653 is not set.
    • The ignition is ON for more than 2 seconds .
    • The battery voltage is between 10-16 volts.

P0653

    • DTC P0652 is not set.
    • The ignition is ON for more than 2 seconds .
    • The battery voltage is between 10-16 volts.

Conditions for Setting the DTC

P0652

The ECM detects the 5-volt reference 2 circuit voltage is less than 4.5 volts.

P0653

The ECM detects the 5-volt reference 2 circuit voltage is more than 5.5 volts.

Action Taken When the DTC Sets

DTC P0652 and P0653 are Type A DTCs.

Conditions for Clearing the MIL/DTC

DTC P0652 and P0653 are Type A DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Control Module Connector End Views
    •  Engine Controls Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Verification

    • The engine starts and runs.
    • Observe the 5-Volt Reference 2 Circuit Status parameter with a scan tool. The parameter should display OK.

Circuit/System Testing

  1. Turn OFF the ignition for 30 seconds or until the ECM powers down.
  2. Disconnect the accelerator pedal position (APP) sensor.
  3. Turn ON the ignition, with engine OFF and measure the voltage from the 5-volt reference circuit of the APP sensor 2 to a good ground with a DMM.
  4. If the voltage measures 4.7-5.2 volts, replace the APP sensor.
  5. With the DMM still connected to the 5-volt reference circuit, disconnect all other components connected to the 5-volt reference 2, one at a time. Refer to Diagnostic Fault Information.
  6. If voltage changes when one of the above components is disconnected, replace the component. Refer to the appropriate replacement procedure.
  7. Test the 5-volt reference 2 circuits for a short to ground or a short to voltage.
  8. If no problem was found in the 5-volt reference 2 circuit , replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Accelerator Pedal Position Sensor Replacement
    •  Crankshaft Position Sensor Replacement
    •  Control Module References for ECM replacement, setup, and programming