GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The engine control module (ECM) provides 5 volts to the following sensors:

    • The accelerator pedal position (APP) sensor 3
    • The camshaft position (CMP) sensor

These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together inside the ECM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt reference circuits. The ECM monitors the voltage on the 5-volt reference circuit. If the ECM detects a low voltage condition, DTC P0698 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0698 5-Volt Reference 3 Circuit Low Voltage

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.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Observe the Freeze Frame/Failure records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  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.

Did the DTC fail this ignition?

--

Go to Step 3

Go to Intermittent Conditions

3

  1. Turn OFF the ignition.
  2. Disconnect the accelerator pedal position (APP) sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the 5-Volt Reference 3 parameter with a scan tool.

Is the 5-Volt Reference 3 parameter within the specified range?

4.5-4.7 V

Go to Step 8

Go to Step 4

4

  1. Disconnect the camshaft position (CMP) sensor.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the 5-Volt Reference 3 parameter with a scan tool.

Is the 5-Volt Reference 3 parameter within the specified range?

4.5-4.7 V

Go to Step 9

Go to Step 5

5

Test the 5-volt reference circuit of the camshaft position sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 6

6

Test the 5-volt reference circuit for the accelerator pedal position (APP) sensor 3 for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

7

Replace the engine control module (ECM). Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 10

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8

Replace the APP sensor. Refer to Accelerator Pedal Position Sensor Replacement .

Did you complete the replacement?

--

Go to Step 10

--

9

Replace the CMP sensor. Refer to Camshaft Position Sensor Replacement .

Did you complete the replacement?

--

Go to Step 10

--

10

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  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.

Did the DTC fail this ignition?

--

Go to Step 3

Go to Step 11

11

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK