The exhaust gas recirculation (EGR) valve is driven by the EGR motor and the EGR motor is controlled by the engine control module (ECM). The EGR position sensor generates signal according to the position of the EGR motor and is sent to the ECM. The EGR valve has the following circuits:
• | The EGR motor U position drive circuit |
• | The EGR motor V position drive circuit |
• | The EGR motor W position drive circuit |
• | A 5-volt reference circuit |
• | A low reference circuit |
• | The EGR motor U position signal circuit |
• | The EGR motor V position signal circuit |
• | The EGR motor W position signal circuit |
The ECM supplies 5 volts to the EGR position sensor on the 5-volt reference circuit. The ECM also provides a ground on the low circuit. The EGR position sensor provides a signal to the ECM on the signal circuits. The ECM decides the EGR valve position according to the 3 signals (U, V, W) conditions. If the ECM detects incorrect EGR position sensor signals, this DTC will set.
This diagnostic procedure supports the following DTC:
DTC P2901 Exhaust Gas Recirculation (EGR) Position Sensor Performance
• | The ignition is ON. |
• | The battery voltage is between 10-16 volts. |
The EGR motor U, V, and P position signals are all high or low.
• | The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
• | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. |
• | The ECM closes the EGR valve and stops the EGR motor. |
• | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
• | Clear the MIL and the DTC with a scan tool. |
Step | Action | Yes | No | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||||||
2 |
Is DTC P0641 also set? | Go to DTC P0641 | Go to Step 3 | ||||||||
3 |
Did you find and correct the condition? | Go to Step 10 | Go to Step 4 | ||||||||
4 |
Did you find and correct the condition? | Go to Step 10 | Go to Step 5 | ||||||||
5 |
Did you find and correct the condition? | Go to Step 10 | Go to Step 6 | ||||||||
6 |
Was a condition found? | Go to Intermittent Conditions | Go to Step 7 | ||||||||
7 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | Go to Step 8 | -- | ||||||||
8 |
Did the DTC fail this ignition? | Go to Step 9 | Go to Step 11 | ||||||||
9 |
Important: The new ECM must be programmed. Replace the ECM. Refer to Engine Control Module Programming and Setup in Programming and Setup, Engine Control Module Replacement/Restore Fuel Rate Data , and Fuel Injector Flow Rate Programming . Did you complete the replacement? | Go to Step 10 | -- | ||||||||
10 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 11 | ||||||||
11 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK |