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

APP Sensor 2 - 5-Volt Reference

P0117, P0462, P0522, P0652, P011A, P2454

P2138

P2127

P0118, P0653, P011A, P244B, P2455

--

Oil Pressure Sensor - 5-Volt Reference

P0117, P0462, P0522, P0652, P011A, P2454

P0522

P0522

P0118, P0522, P0653, P011A, P244B, P2455

--

Fuel Rail Pressure Sensor - 5-Volt Reference

P0117, P0462, P0522, P0652, P011A, P2454

P0087, P0192

P0193

P0118, P0653, P011A, P2455

--

DPF Differential Pressure Sensor

P0117, P0462, P0652, P011A P2454

P2453, P244B

P2454

P0118, P0653, P011A P2455

--

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

    • The ignition is ON.
    • The diagnostics run continuously.

Conditions for Setting the DTC

P0652

    • The ECM detects the 5-volt reference 2 circuit voltage is less than 4.7 volts.
    • The above condition is present for 2 seconds.

P0653

    • The ECM detects the 5-volt reference 2 circuit voltage is more than 5.2 volts.
    • The above condition is present for 2 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.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

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

Important: Additional DTCs will set when disconnecting the components.

  1. Ignition OFF, disconnect the harness connector of all appropriate sensors for the applicable DTC.
  2. Important: A short to voltage on the signal circuit of certain components may cause this DTC to set.

  3. Ignition ON, measure for 4.8-5.2 volts between one of the 5-volt reference circuits and ground.
  4. If the voltage is less than the specified range, test for a short to ground on all the 5-volt reference circuits. If all circuits test normal, replace the ECM.
    If the voltage is greater than the specified range, test for a short to voltage on all the 5-volt reference circuits. If all circuits test normal, replace the ECM.
  5. Connect each component associated with the 5-volt reference circuit, one at a time, while monitoring the voltage. The voltage should not change more than 1 volt.
  6. If the voltage display increases greater than the specified value when a component is connected, test the signal circuit for a short to voltage. If all circuits test normal, replace the ECM.
    If the voltage display decreases more than the specified value when a component is connected, replace the component.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Accelerator Pedal Position Sensor Replacement
    •  Engine Oil Pressure Sensor and/or Switch Replacement
    •  Exhaust Pressure Differential Sensor Replacement
    •  Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement
    •  Control Module References for ECM replacement, setup, and programming