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 a signal according to the position of the EGR motor. 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 voltage to the EGR motor on the EGR motor drive circuits. The EGR valve is controlled by the time of voltage supply from the ECM to the EGR motor. When the time of voltage supply increases, the EGR valve position decreases. The ECM detects the actual EGR valve operation with the mass air flow (MAF) ratio. If the ECM detects an excessively small deviation of the MAF ratio, this DTC will set.
This diagnostic procedure supports the following DTC:
DTC P2903 Exhaust Gas Recirculation (EGR) Valve Stuck
• | DTCs P0087, P0088, P0091, P0092, P0107, P0108, P0112, P0113, P0117, P0118, P0182, P0183, P0192, P0193, P0201, P0202, P0203, P0204, P0205, P0206, P0234, P0522, P0523, P0606, P0641, P1087, P1088, P1261, P1263, P1264, P1265, P1266, P2003, P2004, P2007, P2008, P2011, P2012, P2564, P2565, P2900, P2901, P2902, P2921, P2923 is not set. |
• | The ignition switch is ON. |
• | The battery voltage is between 10-16 volts. |
• | The engine is running. |
• | The EGR control is normal. |
The deviation of the MAF ratio when the EGR valve is 20 percent open, and the MAF ratio when the EGR valve is full close is less than threshold.
• | 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 control. |
• | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
• | Clear the MIL and the DTC with a scan tool. |
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 1 | |||||||||
Did the DTC fail this ignition? | Go to Step 3 | Go to Intermittent Conditions | |||||||||
3 |
Did you find and correct the condition? | Go to Step 8 | Go to Step 4 | ||||||||
4 |
Was a condition found? | Go to Step 6 | Go to Step 5 | ||||||||
5 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | Go to Step 6 | -- | ||||||||
6 |
Did the DTC fail this ignition? | Go to Step 7 | Go to Step 9 | ||||||||
7 |
Important: The new ECM must be programmed. Replace the ECM. Refer to Engine Control Module 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 8 | -- | ||||||||
8 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 9 | ||||||||
9 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK |