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
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 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 poor connection at the PCM or at the EGR Valve--Inspect the harness connectors for the following conditions: |
| - | Backed-out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly-formed terminals |
| - | Damaged terminals |
| - | Poor terminal-to-wire connections |
| • | A damaged harness--Inspect the wiring harness for damage. If the harness appears OK, connect a DMM and test the circuit continuity while moving the connectors and the wiring harnesses that are related to the EGR valve. A change in the display will indicate the location of the malfunction. |
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Test Description
The numbers below refer to the step numbers on the Diagnostic Table:
-
This step verifies that the malfunction is present.
-
If DTC P0405 will only set during certain conditions, the malfunction may be intermittent. Refer to Diagnostic Aids. If there is no intermittent wiring problem, inspect for a poor connection at the PCM or at the EGR valve.
-
This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read-only memory (EEPROM). When you replace the PCM, you must program the new PCM.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||
|
Important: If DTC P1635 5 Volt Reference Circuit is set, perform that diagnostic first.
Does the desired EGR position remain close to the actual EGR position at all commanded positions? | -- | |||||||||
Does the DTC reset? | -- | Go to Diagnostic Aids | ||||||||
4 |
Is the voltage at the specified value? | 5V | ||||||||
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 |
Is the 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 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 signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | -- | |||||||
13 |
Did you find and correct the condition? | -- | ||||||||
14 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Important: If the EGR valve shows signs of excessive heat, check the exhaust system
for blockage, using the procedure found in the
Restricted Exhaust System Check
. If you find a restriction, repair
the condition. Check for an injector which is open due to one of the following
conditions:
Did you find and correct the condition? | -- | -- | |||||||
15 |
Did you find and correct the condition? | -- | ||||||||
16 | Locate and repair the short to ground in the 5-volt reference A circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | -- | |||||||
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. Did you complete the replacement? | -- | -- | ||||||||
19 |
Does the DTC reset? | -- | System OK |
