P0698

P0698-SENSOR REFERENCE VOLTAGE 3 TOO LOW





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on.

- Set Condition:
The ECM detects low voltage on the Sensor Supply #3 circuit for 0.10 seconds





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Theory of Operation

The ECM contains 3 internal 5-Volt Sensor Supply sources. Each 5-Volt Supply source is split into parallel circuits to provide 5 volts to multiple sensors. Sensor Supply 3 provides 5 volts to the Inlet Pressure Sensor, Exhaust Gas Pressure Sensor, Oil Pressure Sensor, EGR Airflow Control Servo Motor Position Sensor, and the Accelerator Pedal Position Sensor #2.

Diagnostic Test

1. CHECK FOR ACTIVE DTC
Turn the ignition on.
With the scan tool, erase ECM DTCs.
Turn the ignition off for 10 seconds.
Turn the ignition on.
With the scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Go To2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Intermittent Condition

2. ACCELERATOR PEDAL POSITION SENSOR




Turn the ignition off.
Disconnect the APP Sensor harness connector.
Turn the ignition on.
Measure the voltage of the (F856) Accelerator Pedal Position Sensor No. 2 5 Volt Supply circuit in the APP Sensor harness connector.
Is the voltage above 4.6 volts?

Yes

- Replace the Accelerator Pedal Position Sensor.
- Perform the ECM VERIFICATION TESTVerification Tests

No

- Go To3

3. EXHAUST GAS PRESSURE SENSOR




Turn the ignition off.
Disconnect the Exhaust Gas Pressure Sensor harness connector.
Turn the ignition on.
Measure the voltage of the (F858) Exhaust Gas Pressure Sensor 5 Volt Supply circuit in the Exhaust Gas Pressure Sensor harness connector.
Is the voltage above 4.6 volts?

Yes

- Replace the Exhaust Gas Pressure Sensor.
- Perform the ECM VERIFICATION TESTVerification Tests

No

- Go To4

4. INLET AIR PRESSURE SENSOR




Turn the ignition off.
Disconnect the Inlet Air Pressure Sensor harness connector.
Turn the ignition on.
Measure the voltage of the (K668) Inlet Air Pressure Sensor 5 Volt Supply circuit in the Air Pressure Sensor harness connector.
Is the voltage above 4.6 volts?

Yes

- Replace the Inlet Air Pressure Sensor.
- Perform the ECM VERIFICATION TESTVerification Tests

No

- Go To5

5. OIL PRESSURE SENSOR




Turn the ignition off.
Disconnect the Oil Pressure Sensor harness connector.
Turn the ignition on.
Measure the voltage of the (F851) Oil Pressure Sensor 5 Volt Supply circuit in the Oil Pressure Sensor harness connector.
Is the voltage above 4.6 volts?

Yes

- Replace the Oil Pressure Sensor.
- Perform the ECM VERIFICATION TESTVerification Tests

No

- Go To6

6. EGR AIRFLOW CONTROL VALVE




Turn the ignition off.
Disconnect the EGR Airflow Control Valve harness connector.
Turn the ignition on.
Measure the voltage of the (K313) EGR Airflow Control Valve Supply circuit in the EGR Airflow Control Valve harness connector.
Is the voltage above 4.6 volts?

Yes

- Replace the EGR Airflow Control Valve.
- Perform the ECM VERIFICATION TESTVerification Tests

No

- Go To7

7. 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND




Turn the ignition off.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the (F856) Accelerator Pedal Position Sensor No. 2 5 Volt Supply circuit.
Measure the resistance between ground and the (F858) Exhaust Gas Pressure Sensor 5 Volt Supply circuit.
Measure the resistance between ground and the (K668) Inlet Air Pressure Sensor 5 Volt Supply circuit.
Measure the resistance between ground and the (F851) Oil Pressure Sensor 5 Volt Supply circuit.
Measure the resistance between ground and the (K313) EGR Airflow Control Valve Supply circuit.
Is the resistance above 1000 ohms for each circuit?

Yes

- Go To8

No

- Repair the 5-Volt Supply circuit for a short to ground.
- Perform the ECM VERIFICATION TESTVerification Tests

8. ENGINE CONTROL MODULE (ECM)
Inspect the (F856) Accelerator Pedal Position Sensor No. 2 5 Volt Supply circuit between the Accelerator Pedal Position Sensor and the ECM.
Inspect the (F858) Exhaust Gas Pressure Sensor 5 Volt Supply circuit between the Exhaust Gas Pressure Sensor and the ECM.
Inspect the (K668) Inlet Air Pressure Sensor 5 Volt Supply circuit between the Inlet Air Pressure Sensor and the ECM.
Inspect the (F851) Oil Pressure Sensor 5 Volt Supply circuit between the Oil Pressure Sensor and the ECM.
Inspect the (K313) EGR Airfoil Control Valve Supply circuit between the EGR Airfoil Control Valve and the ECM.
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the ECM VERIFICATION TESTVerification Tests

No

- Replace and program the Engine Control Module.
- Perform the ECM VERIFICATION TESTVerification Tests