P0406-EGR POSITION SENSOR CIRCUIT HIGH
For a complete wiring diagram Refer to Section 8W.
Possible Causes
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(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT
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(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
|
(K34) EGR POSITION SENSOR SIGNAL CIRCUIT OPEN
|
(K900) SENSOR GROUND CIRCUIT OPEN
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EGR SOLENOID ASSEMBLY
|
PCM
|
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
Diagnostic Test
1.
EGR POSITION SENSOR VOLTAGE ABOVE 4.5 VOLTS
Start the engine.
With the scan tool, read the EGR Position Sensor voltage.
Is the voltage above 4.5 volts?
Yes
No
2.
(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT
Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Disconnect the C1 and C2 PCM harness connectors.
Measure the resistance between the (K34) EGR Position Sensor Signal circuit and the (F856) 5-volt Supply circuit in the EGR Solenoid harness connector.
Is the resistance below 100 ohms?
Yes
No
3.
(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Ignition on, engine not running.
Measure the voltage on the (K34) EGR Sensor Signal circuit in the EGR Solenoid harness connector.
Is the voltage above 0 volts?
Yes
No
4.
EGR SOLENOID ASSEMBLY
Turn the ignition off.
Connect the PCM harness connectors.
Connect a jumper wire between the (K34) EGR Position Sensor Signal circuit and the (K900) Sensor ground circuit.
With the scan tool, monitor the EGR Position Sensor voltage.
Ignition on, engine not running.
Is the voltage below 0.5 of a volt?
Yes
No
5.
(K34) EGR POSITION SENSOR SIGNAL CIRCUIT OPEN
Turn the ignition off.
Disconnect the C2 PCM harness connector.
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 (K34) EGR Position Sensor Signal circuit from the EGR Solenoid harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
No
6.
(K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor ground circuit from the EGR Solenoid harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 30 ohms?
Yes
No
7.
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
No
8.
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
No