The PCM monitors the EGR valve pintle position input to ensure that the valve responds properly to commands from the PCM. The Linear EGR valve is controlled by using an ignition positive driver and ground circuit within the PCM. The driver has the ability to detect an electrical malfunction in the ignition positive or ground circuit. If an electrical malfunction occurs, the driver signals the PCM to set DTC P0403.
The ignition switch is in Crank or Run.
• | EGR control voltage is incorrect. |
• | The above condition is present for longer than 20 seconds. |
• | The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed. |
• | The PCM will disable EGR for the ignition cycle. |
• | The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data. |
• | The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been 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 the scan tool Clear Info function or by disconnecting the PCM battery feed. |
• | Poor connection at PCM or EGR Valve. |
• | Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wore 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 display will indicate the location of the malfunction. |
The numbers below refer to the step numbers on the Diagnostic Table:
Verifies that the malfunction is present.
If DTC P0403 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. Refer to Powertrain Control Module Replacement/Programming .
Step | Action | Value(s) | Yes | No | ||||
---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain OBD System Check performed? | -- | ||||||
With the engine idling, observe Actual EGR Position on the scan tool. Is Actual EGR Position at the specified value? | 0% | |||||||
Does Desired EGR Position remain close to Actual EGR Position at all commanded positions? | -- | |||||||
Does the scan tool indicate DTC P0403 failed this ignition? | -- | Go to Diagnostic Aids | ||||||
5 |
Is the test light on with the commanded EGR valve position at 100%? | -- | ||||||
6 | Probe the EGR valve ground circuit at the EGR valve harness connector with a test light to battery positive voltage. Is the test light on? | -- | ||||||
7 | Probe the EGR valve control circuit at the EGR valve harness connector with a test light to battery positive voltage. Is the test light on? | -- | ||||||
8 |
Was a problem found? | -- | ||||||
9 |
Is the test light on? | -- | ||||||
10 |
Was a problem found? | -- | ||||||
11 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Is the action complete? | -- | -- | |||||
12 | Locate and repair the short to voltage in the EGR valve control circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||
13 |
Is the test light on? | -- | ||||||
14 |
Is the test light on? | -- | ||||||
15 |
Was a problem found? | -- | ||||||
16 | Locate and repair the short to voltage in the EGR valve ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||
17 |
Was a problem found? | -- | ||||||
18 | Locate and repair the short to ground in the EGR valve control circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||
19 |
Was a problem found? | -- | ||||||
Important: : The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | -- | ||||||
21 |
Does the scan tool indicate DTC P0403 failed this ignition? | -- | System OK |