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Stonyman
Stonyman, Ase Certified Master
Category: Chrysler
Satisfied Customers: 723
Experience:  Certified Ase Master, 23 years exp. Pa state and emissions lic. Specializing in Chrysler/Dodge/Jeep
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2002 PT Cruiser - Check engine light is on - code P0401 EGR

This answer was rated:

2002 PT Cruiser - Check engine light is on - code P0401 EGR flow Insufficient. Fuel mileage is less than normal. Removed and cleaned EGR valve and tube. Did not appear to be that dirty or broken. Applying vacuum to diaphram causes valve to open as it should and it re-closes when vacuum is removed. Reinstalled on car, code came back. What else could cause this problem?

Hi here is a list of possible failures, but usually it's a bad egr valve(99%). Ours(factory) come complete with solenoid. I am also attaching some diagnostics too. Let me know if you need anything else.

 

P0401 - EGR SYSTEM FAILURE

When Monitored: With the engine temperature greater than 82° C (180° F), and the

ambient temperature above 32° C (89° F), the engine is in closed loop. The O2 sensor is

operational, and the engine is under a steady load with the throttle open, and the 02

controller is not at or near its limits.

Set Condition: Conditions are met, the EGR is turned off and on momentarily. The

oxygen sensor signal is monitor for changes in its output signal during this test. If no

significant change or too much change is seen, a flag is set.

POSSIBLE CAUSES

INTERMITTENT CONDITION

EGR SOLENOID VACUUM SUPPLY

EGR VALVE OPERATION (CLOSED)

EGR VALVE OPERATION (OPEN)

FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN

EGR SOLENOID CONTROL CIRCUIT SHORTED TO VOLTAGE

EGR SOLENOID CONTROL CIRCUIT OPEN

EGR SOLENOID (CLOSED)

EGR SOLENOID CONTROL CIRCUIT SHORT TO GND

EGR SOLENOID (OPEN)

PCM

PCM (CLOSED)

TEST ACTION APPLICABILITY

1 Turn the ignition on.

With the DRBIIIt, read DTC's.

Is the Good Trip displayed and equal to zero?

All

Yes ! Go To 2

No ! Go To 12

2 Start the engine.

Allow the engine to reach operating temperature.

Does the engine run rough or stall at idle?

All

Yes ! Go To 3

No ! Go To 6

 

3 Disconnect the vacuum hose from the EGR Valve.

Start the engine and allow it to idle.

Does the engine run rough or stall at idle?

All

Yes ! Remove the EGR Valve and inspect the valve for an obstruction

that would keep the valve open. If OK, replace the EGR Valve.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No ! Go To 4

4 Turn the ignition off.

Disconnect the PCM harness connector.

Disconnect the EGR Solenoid harness connector.

Measure the resistance of the EGR Solenoid Control circuit in the EGR Solenoid

harness connector to ground.

Is the resistance below 5.0 ohms?

All

Yes ! Repair the EGR Solenoid Control circuirt for a short to ground.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No ! Go To 5

5 Turn the ignition off.

Disconnect the EGR Solenoid harness connector.

Using a 12-volt test light connected to 12-volts, probe the EGR Solenoid Control

circuit.

Turn the ignition on.

With the DRBIIIt, actuate the EGR Solenoid.

Observe the test light.

Does the test light flash on and off?

All

Yes ! Replace the EGR Solenoid.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No ! Replace and program the Powertrain Control Module in accordance

with the Service Information.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

6 Turn the ignition off.

Disconnect the EGR Solenoid vacuum supply at the EGR Solenoid.

Connect a vacuum gauge to the EGR Solenoid vacuum supply.

Start the engine.

Observe the vacuum gauge.

Does the vacuum gauge read above 109?

All

Yes ! Go To 7

No ! Repair the EGR Solenoid vacuum supply.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

7 Disconnect the vacuum hose from the EGR Valve. Inspect the vacuum hose for any

obstructions.

Connect a Vacuum Pump to the EGR Valve.

Using the Vacuum Pump, apply vacuum to the EGR Valve.

Does the engine run rough or stall at idle?

All

Yes ! Go To 8

No ! Remove the EGR Valve and inspect the valve for an obstruction

that would keep the valve from opening. If OK, replace the EGR

Valve.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

 

8 Turn the igntion off.

Disconnect the EGR Solenoid harness connector.

Turn the ignition on.

Using a 12 volt Test Light connected to ground, probe the Fused Ignition Switch

Output circuit in the EGR Solenoid harness connector.

Does the 12 volt test light illuminate?

All

Yes ! Go To 9

No ! Repair the Fused Ignition Switch Output circuit for an open.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

9 Turn the ignition off.

Disconnect the EGR Solenoid harness connector.

Turn the ignition on.

Measure the voltage of the EGR Solenoid Control circuit in the EGR Solenoid

connector.

Is the voltage above 1.0 volts?

All

Yes ! Repair the EGR Solenoid Control circuit for a short to voltage.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No ! Go To 10

10 Turn the ignition off.

Disconnect the PCM harness connector.

Disconnect the EGR Solenoid harness connector.

Measure the resistance of the EGR Solenoid Control circuit between the PCM

harness connector and the EGR Solenoid harness connector.

Is the resistance below 5.0 ohms?

All

Yes ! Go To 11

No ! Repair the EGR solenoid control circuit for an open.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

11 Turn the ignition off.

Disconnect the EGR Solenoid harness connector.

Using a 12-volt test light connected to 12-volts, probe the EGR Solenoid Control

circuit in the EGR Solenoid harness connector.

Turn the ignition on.

With the DRBIIIt, actuate the EGR Solenoid.

Observe the test light.

Does the test light flash on and off.

All

Yes ! Inspect the EGR Solenoid Back Pressure hose and tube for

obstructions or damage. If OK, replace the EGR Solenoid.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No ! Replace and program the Powertrain Control Module in accordance

with the Service Information.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

 

12 NOTE: Inspect the exhaust system for leaks.

WARNING: KEEP CLEAR OF THE ENGINE'S MOVING PARTS.

NOTE: The conditions that set the DTC are not present at this time. The

following list may help in identifying the intermittent condition.

With the engine running at normal operating temperature, monitor the DRBIIIt

parameters related to the DTC while wiggling the wiring harness. Look for parameter

values to change and/or a DTC to set.

Review the DRBIIIt Freeze Frame information. If possible, try to duplicate the

conditions under which the DTC was set.

Refer to any Technical Service Bulletins (TSB) that may apply.

Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or

partially broken wires.

Visually inspect the related wiring harness connectors. Look for broken, bent, pushed

out, or corroded terminals.

Were any of the above conditions present?

All

Yes ! Repair as necessary

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No ! Test Complete.

 

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