Jeep Grand Cherokee WK. Manual — part 965
P0404-EGR POSITION SENSOR PERFORMANCE (CONTINUED)
For the Engine circuit diagram (Refer to 9 - ENGINE - SCHEMATICS AND DIAGRAMS).
For a complete wiring diagram Refer to Section 8W.
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.
Possible Causes
EXCESSIVE RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT
(K35) EGR SOLENOID CONTROL CIRCUIT
(K34) EGR SENSOR SIGNAL CIRCUIT OPEN
(K34) EGR SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
(K900) SENSOR GROUND CIRCUIT OPEN
EGR SOLENOID ASSEMBLY
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.
ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Yes
>> Go To 2
No
>> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.
EGR POSITION VOLTAGE
NOTE: Diagnose all other EGR DTC(s) before continuing.
Start the engine.
With a scan tool, read the EGR Position Sensor voltage.
Choose a conclusion that best matches the EGR voltage reading.
Below 3.5 volts
Go To 3
Between 3.5 volts to 4.3 volts
Go To 5
Above 4.3 volts
Go To 6
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ENGINE ELECTRICAL DIAGNOSTICS
WK
P0404-EGR POSITION SENSOR PERFORMANCE (CONTINUED)
3.
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.
Is the resistance below 5.0 ohms?
Yes
>> Go To 4
No
>> Repair the excessive resistance in the (F856) 5-volt Sup-
ply circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
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.
Is the resistance below 5.0 ohms?
Yes
>> Repair the short to ground in the (K34) EGR Sensor Sig-
nal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
No
>> Replace the EGR Assembly.
Perform the POWERTRAIN VERIFICATION TEST. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
WK
ENGINE ELECTRICAL DIAGNOSTICS
9 - 457
P0404-EGR POSITION SENSOR PERFORMANCE (CONTINUED)
5.
(K35) EGR SOLENOID CONTROL CIRCUIT
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.
Does EGR Solenoid operate while actuating and then turn off when actuation test is stopped?
a. Yes
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
>> Refer to the P0403-EGR Control Circuit diagnostic procedure and continue.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
6.
(K34) EGR SENSOR SIGNAL CIRCUIT
Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Ignition on, engine not running.
Measure the voltage of the (K34) EGR Sensor Signal circuit in the
EGR Solenoid harness connector.
Is the voltage above 4.30 volts?
Yes
>> Go To 7
No
>> Go To 8
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ENGINE ELECTRICAL DIAGNOSTICS
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P0404-EGR POSITION SENSOR PERFORMANCE (CONTINUED)
7.
(K900) SENSOR GROUND CIRCUIT OPEN
Turn the ignition off.
Disconnect the C2 PCM harness 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 Miller Special
Tool #8815 to perform diagnosis.
Measure the resistance of the (K900) Sensor ground circuit from the
EGR Solenoid harness connector to the appropriate terminal of special
tool #8815.
Is the resistance below 5.0 ohms?
Yes
>> Replace the EGR Assembly.
Perform the POWERTRAIN VERIFICATION TEST. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
No
>> Repair the open in the (K900) Sensor ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
8.
(K34) EGR SENSOR SIGNAL CIRCUIT OPEN
Turn the ignition off.
Disconnect the C2 PCM harness 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 Miller Special
Tool #8815 to perform diagnosis.
Measure the resistance of the (K34) EGR Sensor Signal circuit from
the EGR Solenoid harness connector to the appropriate terminal of
special tool #8815.
Is the resistance below 5.0 ohms?
Yes
>> Go To 9
No
>> Repair the open in the (K34) EGR Sensor Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
WK
ENGINE ELECTRICAL DIAGNOSTICS
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