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

--

A/C Pressure Sensor - 5-Volt Reference

P0652

--

P0532

P0653

--

Oil Pressure Sensor - 5-Volt Reference

P0117, P0462, P0652, P0522, 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

    •  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

  1. The engine starts and runs.
  2. Observe the 5-Volt Reference 2 Circuit Status parameter with a scan tool. The parameter should display OK.
  3. Engine running, observe the DTC information with a scan tool. DTCs P0652 or P0653 should not set.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

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
    •  Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement
    •  Exhaust Pressure Differential Sensor Replacement
    •  Engine Oil Pressure Sensor and/or Switch Replacement
    •  Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement
    •  Control Module References for ECM replacement, setup, and programming.