P0405

P0405-EGR POSITION SENSOR CIRCUIT LOW

For a complete wiring diagram refer to Diagrams/Electrical.

- When Monitored:

With the ignition on. Battery voltage above 10.0 volts.

- Set Condition:

EGR Position Sensor Signal is less than 0.1 of a volt. One trip Fault.

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. ACTIVE DTC

Turn the ignition on.

With the scan tool, select View DTCs. Record DTC and Freeze Frame information.

Start the engine and allow it to reach operating temperature.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

WARNING: The normal operating temperature of the EGR system is very high. Never work around or attempt to service any part of the EGR system until it has cooled.

NOTE: Attempt to operate the vehicle under conditions similar to which the DTC was set.

NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.

With a scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Go To 10

2. (K857) 5-VOLT SUPPLY CIRCUIT

Turn the ignition off.

Disconnect the EGR Solenoid harness connector.

Ignition on, engine not running.

Measure the voltage of the (K857) 5-volt Supply circuit in the EGR Solenoid harness connector.

Is the voltage between 4.5 to 5.2 volts?

Yes

- Go To 3

No

- Go To 7

3. EGR POSITION

With the scan tool, monitor the EGR Position Sensor voltage.

NOTE: The sensor voltage should be approximately 5.0 volts(plus or minus .1 volt) with the connector disconnected.

Does the scan tool display the voltage as described above?

Yes

- Replace the EGR Solenoid Assembly.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 4

4. (K34) EGR SIGNAL CIRCUIT SHORTED TO GROUND

Turn the ignition off.

Disconnect the C2 PCM harness connector.

Measure the resistance between ground and the (K34) EGR Signal circuit in the EGR Solenoid harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short to ground circuit in the (K34) EGR Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 5

5. (K34) EGR SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT

Measure the resistance between the (K34) EGR Signal circuit and (K900) Sensor ground circuit in the EGR Solenoid harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short between the (K900) Sensor ground and the (K34) EGR Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 6

6. EXCESSIVE RESISTANCE IN THE (K34) EGR POSITION SENSOR SIGNAL CIRCUIT

Turn the ignition off.

Disconnect the C1 PCM harness connector.

Measure the resistance between ground and the (K857) 5-volt Supply circuit in the EGR Solenoid harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short to ground in the (K857) 5-volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 8

8. (K857) 5-VOLT SUPPLY CIRCUIT OPEN

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K857) 5-volt Supply circuit from the EGR Solenoid harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes

- Go To 9

No

- Repair the open in the (K857) 5-volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

9. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

10. EGR POSITION SENSOR SWEEP

NOTE: The engine will run rough and possibly stall in the following test. Feather the accelerator pedal to keep the engine from stalling.

Start the engine.

With the scan tool, enter System Test and then EGR System Test. Push the 4=VARIABLE function.

Monitor the EGR voltage while slowly pushing the up arrow.

Is the voltage change smooth?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

- Replace the EGR Solenoid Assembly.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test