Circuit Description
The powertrain control module (PCM) monitors the exhaust gas recirculation (EGR) valve pintle position input to ensure that the valve responds properly to commands from the PCM and to detect a fault if the pintle position sensor circuit is open or shorted. If the PCM detect an excessively low EGR position sensor signal voltage, this diagnostic trouble code (DTC) will set.
Conditions for Running the DTC
| • | The system voltage is greater than 11 volts. |
| • | The ignition is ON. |
Conditions for Setting the DTC
| • | The EGR position sensor is less than 0.35 volts at any time. |
| • | The condition is present for more than 20 seconds. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
|
Important: If a DTC P1635 is set diagnose that DTC first.
Does the scan tool indicate that the EGR position sensor voltage is less than the specified value? | 0.35 V | Go to Step 4 | Go to Step 3 | |
3 |
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions |
4 |
Does the scan tool indicate that the EGR position sensor is near the specified value? | 100 % | Go to Step 10 | Go to Step 5 |
5 |
Does the DMM display voltage near the specified value? | 5 V | Go to Step 9 | Go to Step 6 |
6 | Test the 5-volt reference circuit of the EGR position sensor for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 7 |
7 | Test all 5-volt reference circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 8 |
8 | Connect a DMM between the EGR position sensor 5-volt reference circuit and the EGR position sensor low reference circuit. Observe the voltage while disconnecting all sensors that use a 5-volt reference signal, one at a time. A change in voltage indicates the faulty component. Replace that component as necessary. Refer to the appropriate replacement procedure. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 11 |
9 | Test the EGR pintle position signal circuit for a short to ground, for high resistance, or for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 11 |
10 | Test the EGR valve position signal circuit for a short to the EGR solenoid high control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
11 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
12 | Inspect for poor connections at the harness connector of the EGR valve . Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 |
13 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
14 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
15 |
Does the DTC run and pass? | -- | Go to Step 16 | Go to Step 2 |
16 | With a scan tool, observe the stored information, Capture info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
