P1404
P1404-EGR POSITION SENSOR RATIONALITY CLOSED
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The EGR valve has a position sensor and the EGR position rationality is designed to make sure that the valve moves freely within its operating range. Closed valve position reference check verifies that the valve is within its allowable upper and lower limits. The EGR position rationality test looks for a sustained error relative to commanded valve position.
- When Monitored:
Engine running.
- Set Condition:
The EGR flow or valve movement is not what is expected. A rationality error has been detected for the EGR Open Position Performance. Two trip fault.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. ACTIVE DTC
NOTE: Diagnose and repair any EGR signal circuit high or low DTCs before continuing with this procedure.
1. Turn the ignition on.
2. With the scan tool, select View DTCs. Record DTC and Freeze Frame information.
3. Start the engine and allow it to reach operating temperature.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose fitting clothing. Failure to follow these instructions can result in personal or fatal injury.
WARNING: The normal operating temperature of the EGR system is very high. Never work around or attempt to service any part of the EGR system until it has cooled. Failure to follow these instructions can result in possible serious or fatal injury.
NOTE: Attempt to operate the vehicle under conditions similar to which the DTC was set.
NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.
4. With the scan tool, select View DTCs.
Is the DTC Active or Pending at this time?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.
2. EXCESSIVE RESISTANCE IN THE (F856) 5 VOLT SUPPLY CIRCUIT
1. Turn the ignition off.
2. Disconnect the EGR Solenoid harness connector.
3. Disconnect the C1 and C2 PCM harness connectors.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install PCM Pinout Box 8815 to perform diagnosis.
4. Measure the resistance of the (F856) 5 Volt Supply circuit from the EGR Solenoid harness connector to the appropriate terminal of PCM Pinout Box 8815.
Is the resistance below 5.0 Ohms?
Yes
- Go To 3
No
- Repair the excessive resistance in the (F856) 5 Volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
3. (K35) EGR SOLENOID CONTROL CIRCUIT OPEN
1. Measure the resistance of the (K35) EGR Solenoid Control circuit from the EGR Solenoid harness connector to the appropriate terminal of PCM Pinout Box 8815.
Is the resistance below 5.0 Ohms?
Yes
- Go To 4
No
- Repair the open in the (K35) EGR Solenoid Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
4. (K34) EGR SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
1. Measure the resistance between ground and the (K34) EGR Sensor Signal circuit in the EGR Solenoid harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Repair the short to ground in the (K34) EGR Sensor Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 5
5. (Z42) GROUND CIRCUIT OPEN OR HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the EGR Valve Assembly harness connector.
3. Using a 12-volt test light connected to the 12-volts, check the (Z42) Ground circuit in the EGR Valve Assembly harness connector.
NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Is the test light illuminated and bright?
Yes
- Go To 6
No
- Repair the (Z42) Ground circuit for an open circuit of high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
6. (K35) EGR CONTROL CIRCUIT HIGH RESISTANCE
1. Turn the ignition off.
2. Connect the EGR Valve Assembly connector.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install PCM Pinout Box 8815 along with the Adapter 8815-1 to perform the diagnosis.
3. Using a Voltmeter, perform a voltage drop test by backprobing the (K35) EGR Control circuit at the EGR Valve Assembly harness connector and probing the appropriate terminal of the PCM Pinout Box 8815. Make sure the Voltmeter leads are connected so that positive polarity is displayed on the Voltmeter.
4. Start the engine and allow it to reach operating temperature.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in possible serious or fatal injury.
5. With the scan tool, perform the EGR System Test.
6. Select OPEN to open the EGR valve.
7. Monitor the circuit voltage on the Voltmeter.
Is the voltage below 0.5 of a Volt when the valve was opened during the system test?
Yes
- Go To 7
No
- Repair the (K35) EGR Control circuit for excessive resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
7. EGR SOLENOID ASSEMBLY
1. Connect the Powertrain Control Module (PCM) connector.
2. Turn the ignition on.
3. With the scan tool, actuate the EGR Valve Solenoid Duty Cycle.
4. Select the Duty Cycle reading of 79.9%
5. Using a 12-volt test light connected to ground, check the (K35) EGR Control circuit in the EGR Valve Assembly harness connector.
NOTE: If the DTC is active, the actuation test may not be allowed by the PCM. If may be necessary to clear the DTCs before starting the actuation.
NOTE: The voltage supplied to the solenoid circuit during the actuation may be less than battery voltage. The test light should be illuminated, but may not be as bright as a direct connection to the battery.
NOTE: The test light should be illuminated and bright proportional to the maximum duty cycle allowed by the scan tool. For example, if the scan tool allows 100% actuation, the brightness should be as bright as a direct connection to the battery. If the scan tool allows a maximum 25% actuation, the brightness should be 25% as bright as a direct connection to the battery.
Is the test light illuminated during the actuation?
Yes
- Go To 8
No
- Verify that there is good pin to terminal contact in the Solenoid and Powertrain Control Module connectors. If OK, replace the EGR Solenoid Assembly.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
8. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the EGR Solenoid Assembly and the Powertrain Control Module (PCM).
- Look for any chafed, pierced, pinched or partially broken wires.
- Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Solenoid and Powertrain Control Module connectors.
- Perform any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.