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
System voltage is greater than 10 volts.
Conditions for Setting the DTC
| • | EGR feedback is less than 0.14 volt 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
| • | A faulty connection at the PCM or the EGR valve--Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. Use a corresponding mating terminal to test for proper terminal tension. |
| • | Inspect the wiring harness for damage. If the harness appears to be OK, connect a digital multimeter (DMM) and check the circuit continuity while moving the connectors and the wiring harnesses related to the EGR valve. A change in the DMM display indicates the location of the malfunction. |
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. If an intermittent wiring problem is not present, check for a faulty 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 replaced, the new PCM must be programmed.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On Board Diagnostic (OBD) System Check performed? | -- | ||||||||
If P1635 is set, perform DTC P1635 5 Volt Reference Circuit first.
Does the Desired EGR Position approximately equal the Actual EGR Position at all commanded positions? | -- | |||||||||
Does the scan tool indicate DTC P0405 failed this ign? | -- | Go to Diagnostic Aids | ||||||||
4 |
Does the voltage equal the specified value? | 5 V | ||||||||
5 | Probe the EGR valve pintle position signal circuit at the EGR valve harness connector with a test lamp connected to B+. Does the test lamp illuminate? | -- | ||||||||
6 |
Does the Actual EGR Position equal the specified value? | 100 percent | ||||||||
7 |
Was a problem found? | -- | ||||||||
8 |
Does the test lamp illuminate? | -- | ||||||||
9 | Probe the 5 volt reference A circuit with a test lamp connected to B+. Does the test lamp illuminate? | -- | ||||||||
10 |
Does the test lamp illuminate? | -- | ||||||||
11 |
Was a problem found? | -- | ||||||||
12 | Locate and correct the short to ground in the EGR valve pintle position signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||
13 |
Was a problem found? | -- | ||||||||
14 |
Important: 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. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the repair? | -- | -- | |||||||
15 |
Was a problem found? | -- | ||||||||
16 | Locate and repair a 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 . Did you complete the repair? | -- | -- | ||||||||
19 |
Does the scan tool indicate DTC P0405 failed this ignition? | -- | System OK |
