Circuit Description
The PCM monitors the 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 detects an excessively low EGR Feedback signal voltage, DTC P0405 will set.
Conditions for Running the DTC
| • | System voltage is greater than 10 volts. |
| • | EGR is enabled. |
Conditions for Setting the DTC
| • | EGR Feedback is less than 0.14 volt at any time. |
| • | The condition is present for longer than 20 seconds. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
| • | Poor connection at PCM or EGR Valve. |
| Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the harness appears to be OK, connect J 39200 DMM and check circuit continuity while moving connectors and wiring harnesses related to the EGR valve. A change in the DMM display will indicate the location of the malfunction. |
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table:
-
Verifies that the malfunction is present.
-
If DTC P0405 will only set under certain conditions, the malfunction may be intermittent; refer to Diagnostic Aids. If an intermittent wiring problem is not present, check for a poor connection at the PCM or the EGR valve.
-
This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
|
Important: If DTC P1635 is set, refer to DTC P1635 5 Volt Reference Circuit first.
Does Desired EGR Position remain close to Actual EGR Position at all commanded positions? | -- | |||
Does the scan tool indicate DTC P0405 failed this ign? | -- | Go to Diagnostic Aids | ||
4 |
Is the voltage at or near the specified value? | 5V | ||
5 | Probe the EGR valve pintle position signal circuit at the EGR valve harness connector with a J 35616-200 test lamp that is connected to B+. Does the test lamp illuminate? | -- | ||
6 |
Is Actual EGR Position at the specified value? | 100% | ||
7 |
Did you find and correct the condition? | -- | ||
8 |
Does the test lamp illuminate? | -- | ||
9 | Probe the 5 volt reference A circuit with a test lamp that is connected to B+. Does the test lamp illuminate? | -- | ||
10 |
Does the test lamp illuminate? | -- | ||
11 |
Did you find and correct the condition? | -- | ||
12 | Locate and correct the short to ground in the EGR valve pintle position circuit. Refer to Wiring Repairs . Is action complete? | -- | -- | |
13 | Check for the following conditions:
If a problem is found, repair as necessary. Refer to Wiring Repairs or Intermittents and Poor Connections Diagnosis . Did you find and correct the condition? | -- | ||
14 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Is action complete? | -- | -- | |
15 |
Did you find and correct the condition? | -- | ||
16 | Locate and repair short to ground in the 5 volt reference A circuit. Refer to Wiring Repairs . Is action complete? | -- | -- | |
17 |
Did you find and correct the condition? | -- | ||
|
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is action complete? | -- | -- | ||
19 |
Does the scan tool indicate DTC P0405 failed this ignition? | -- | System OK |
