Circuit Description
The exhaust gas recirculation (EGR) valve pintle position sensor circuit provides EGR valve opening information to the PCM. The powertrain control module (PCM) supplies a 5 volt reference and a ground circuit for the EGR pintle position sensor. The EGR pintle position sensor varies the voltage relative to the amount commanded by the EGR. The PCM monitors the EGR pintle position sensor input to ensure that the EGR valve responds properly to commands from the PCM and to detect a fault. If the PCM detects an excessively low EGR pintle position signal voltage, DTC P0405 is set.
Conditions for Running the DTC
| • | None of the following DTCs are set: |
| • | Throttle position (TP) sensor DTCs |
| • | Intake air temperature (IAT) sensor DTCs |
| • | Engine coolant temperature (ECT) sensor DTCs |
| • | Mass air flow (MAF) sensor DTCs |
| • | Heated oxygen sensor (HO2S) DTCs |
| • | the required engine run time is met. The time ranges from 45 seconds to 8.5 minutes depending upon the ECT at startup. |
| • | The TP angle is greater than 2%. |
| • | The system voltage is more than 10 volts. |
Conditions for Setting the DTC
| • | The 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 illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has run and failed. |
| • | The PCM disables the EGR for the rest of the ignition cycle. |
| • | The PCM stores the conditions which were present when the DTC set as Freeze Frame and Fail Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns the MIL off during the third consecutive trip in which the diagnostic has run and passed. |
| • | The history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC may be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed. |
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. |
| • | Inspect the wiring harness for damage. If the harness appears to be OK, connect a digital multimeter (DMM) and test the circuit continuity while moving the connectors and wiring harnesses related to the EGR valve. A change in the DMM display indicates the location of the malfunction. |
Test Description
The number(s) below refer to the step number(s) on the Diagnostic Table:
-
Verifies that the malfunction is present.
-
If DTC P0405 only sets under certain conditions, the malfunction may be intermittent. Refer to Diagnostic Aids. If an intermittent wiring problem is not present, test for a faulty connection at the powertrain control module (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 | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||
Does the Desired EGR Position remain close to the 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 equal to the specified value? | 5 V | ||||||||
5 | Use a test lamp connected to B+ in order to probe the EGR valve pintle position circuit at the EGR valve harness connector. Does the test lamp illuminate? | -- | ||||||||
6 |
Is the Actual EGR Position equal to the specified value? | 100% | ||||||||
7 |
Was a problem found? | -- | ||||||||
8 |
Does the test lamp illuminate? | -- | ||||||||
9 | Use a test lamp connected to B+ in order to probe the 5 volt reference B circuit. 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 circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||
13 |
Was a problem found? | -- | ||||||||
14 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Notice: If the EGR valve shows signs of excessive heat, inspect 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. Inspect for an open injector caused by one or more of the
following conditions:
Did you complete the repair? | -- | -- | |||||||
15 |
Was a problem found? | -- | ||||||||
16 | Locate and repair a short to ground in the 5 volt reference B circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||
17 |
Was a problem found? | -- | ||||||||
|
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Did you complete the repair? | -- | -- | ||||||||
19 |
Does the scan tool indicate DTC P0405 Failed This Ign? | -- | System OK |
