P0405-EGR POSITION SENSOR CIRCUIT LOW
For a complete wiring diagram Refer to Section 8W.
Possible Causes
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(F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
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(F856) 5-VOLT SUPPLY CIRCUIT OPEN
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(K34) EGR SIGNAL CIRCUIT SHORTED TO GROUND
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(K34) EGR SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
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EGR POSITION SENSOR
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PCM
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Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
Diagnostic Test
1.
EGR POSITION SENSOR BELOW 0.2 OF A VOLT
Ignition on, engine not running.
With a scan tool, read the EGR Position Sensor voltage.
Is the voltage below 0.2 of a volt?
Yes
No
2.
(F856) 5-VOLT SUPPLY CIRCUIT
Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Ignition on, engine not running.
Measure the voltage of the (F856) 5-volt Supply circuit in the EGR Solenoid harness connector.
Is the voltage between 4.5 to 5.2 volts?
Yes
No
3.
EGR POSITION
With the scan tool, monitor the EGR Position Sensor voltage.
Is the voltage above 4.5 volts?
Yes
No
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
No
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
No
6.
(F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C1 PCM harness connector.
Measure the resistance between ground and the (F856) 5-volt Supply circuit in the EGR Solenoid harness connector.
Is the resistance below 100 ohms?
Yes
No
7.
(F856) 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 (F856) 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
No
8.
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
9.
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