Refer to Engine Controls Schematics
Engine Data Sensors, MAF and EGR
.
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 detects an excessively low EGR feedback signal voltage, DTC P0405 will set.
Conditions for Running the DTC
| • | The engine is running. |
| • | The system voltage is between 10 volts and 18 volts. |
Conditions for Setting the DTC
| • | The EGR feedback 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 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 the PCM or EGR valve--Inspect the harness connectors for: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | Poor terminal to wire connection |
| • | Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
| • | Damaged harness-- Inspect the wiring harness for damage. If the harness appears to be OK, connect a DMM and check the 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. Refer to Wiring Repairs in Wiring Systems. |
Test Description
The numbers below refer to the step numbers 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 | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||
|
Important: Go to DTC P1635 if it sets while the engine is running.
Does the Desired EGR Position remain close to Actual EGR Position at all commanded positions? | -- | |||||||
Does the scan tool indicate DTC P0405 failed this ignition? | -- | Go to Diagnostic Aids | ||||||
4 |
Is the voltage at the specified value? | 5.0 V | ||||||
5 | Probe the EGR valve pintle position circuit at the EGR valve harness connector with a test lamp connected to battery positive voltage. Is the test lamp on? | -- | ||||||
6 |
Is the Actual EGR Position at the specified value? | 100% | ||||||
7 |
Was a problem found? | -- | ||||||
8 |
Is the test lamp on? | -- | ||||||
9 | Probe the 5 volt reference A circuit with a test lamp to battery positive voltage. Is the test lamp on? | -- | ||||||
10 |
Is the test lamp on? | -- | ||||||
11 |
Was a problem found? | -- | ||||||
12 | Locate and correct the short to ground in the EGR valve pintle position circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||
13 |
Was a problem found? | -- | ||||||
14 |
Notice: In order to prevent further damage if the EGR valve shows signs of excessive
heat, check the exhaust system for blockage (possibly a plugged converter)
using the procedure found on the restricted exhaust system check. If the exhaust
system is restricted, repair the cause; one of which might be an injector
which is open due to one of the following reasons:
Replace the EGR valve. Is the action complete? | -- | -- | |||||
15 |
Was a problem found? | -- | ||||||
16 | Locate and repair short to ground in the 5 volt reference A circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||
17 |
Was a problem found? | -- | ||||||
|
Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||||||
19 |
Does the scan tool indicate DTC P0405 failed this ignition? | -- | System OK |
