P1404
P01404-EGR POSITION SENSOR RATIONALITY CLOSEDP01404-EGR Position Sensor Rationality Closed:
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.
POSSIBLE CAUSES
- Excessive resistance in the (F856) 5-volt supply circuit
- (K35) EGR solenoid control circuit open
- (K34) EGR sensor signal circuit shorted to ground
- EGR solenoid assembly
- PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read DTCs.
Q: Is the DTC active at this time?
YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Component Tests and General Diagnostics
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
2. EXCESSIVE RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT
Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
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 Miller Special Tool #8815 to perform diagnosis.
Measure the resistance of the (F856) 5-volt Supply circuit from the EGR Solenoid harness connector to the appropriate terminal of special tool #8815.
Q: 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
Measure the resistance of the (K35) EGR Solenoid Control circuit from the EGR Solenoid harness connector to the appropriate terminal of special tool #8815.
Q: 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
Measure the resistance between ground and the (K34) EGR Sensor Signal circuit in the EGR Solenoid harness connector.
Q: 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. EGR SOLENOID ASSEMBLY
Ignition on, engine not running.
With the scan tool, actuate the EGR Solenoid.
Allow the EGR Solenoid to actuate for at least 15 seconds.
Feel the EGR Solenoid for operation.
Stop actuation.
Q: Does EGR Solenoid operate while actuating and then turn off when actuation test is stopped?
YES: Go To 6
NO: Replace the EGR Solenoid Assembly. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
6. PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Q: 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