Symptom:
P-1398 MISFIRE ADAPTIVE NUMERATOR AT LIMIT
When Monitored and Set Condition:
P-1398 MISFIRE ADAPTIVE NUMERATOR AT LIMIT
When Monitored: Under closed throttle decel; A/C off; engine coolant temp > 23 degrees
C (75 degrees F); longer than 50 seconds after engine start. The speed at which the
deceleration occurs must be sufficient for the given gear range, e.g., > 36 Km/h (36 mph)
in first gear or > 104 Km/h (> 65) in high gear.
Set Condition: When one of the CKP Sensor target windows 15 degrees C (60 degrees F)
has more than 2.86% variance from the reference window.
POSSIBLE CAUSES
CKP SENSOR CONNECTOR OBSERVABLE DEFECT
CKP SENSOR CONNECTOR OBSERVABLE DEFECT
CKP SENSOR DEFECTIVE
CKP SENSOR DEFECTIVE
CKP SENSOR NOT PROPERLY INSTALLED
CKP SENSOR NOT PROPERLY INSTALLED
NOTCHES IN CRANKSHAFT DEFECTIVE
SLOTS IN FLEXPLATE DEFECTIVE
TEST ACTION APPLICABILITY
1 Ignition Off.
Disconnect the Crankshaft Position Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Inspect all Terminals.
Is any Terminal damaged, pushed out or miswired?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Repair as necessary.
Perform Verification Test VER-2A.
No®Go To 2
2 Ignition Off.
Disconnect the Crankshaft Position Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Inspect the Crankshaft Position Sensor for proper Torque and installation.
Is the Crankshaft Position Sensor properly installed?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Go To 3
No®Properly install CKP Sensor.
Perform Verification Test VER-2A.
198
DRIVEABILITY
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TEST ACTION APPLICABILITY
3 Ignition Off.
Remove the CKP Sensor.
Inspect the Slots in the Flexplate for debris, damage or excessive movement.
Is there any debris, damage or excessive movement?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Repair as necessary.
Perform Powertrain Verification Test VER-2A.
No®Go To 4
4 If there are no potential causes remaining, the CKP Sensor is assumed to be
defective.
View repair options.ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Repair
Replace the CKP Sensor.
Perform Verification Test VER-2A.
5 Ignition Off.
Disconnect the Crankshaft Position Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Inspect all Terminals.
Is any Terminal damaged, pushed out or miswired?ENGINE -2.0L and
2.4L I-4 DOHC
Ye s®Repair as necessary.
Perform Verification Test VER-2A.
No®Go To 6
6 Ignition Off.
Disconnect the Crankshaft Position Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Inspect the Crankshaft Position Sensor for proper Torque and installation.
Is the Crankshaft Position Sensor properly installed?ENGINE -2.0L and
2.4L I-4 DOHC
Ye s®Go To 7
No®Properly install CKP Sensor.
Perform Verification Test VER-2A.
7 Ignition Off.
Remove the Crankshaft Position Sensor.
Inspect the notches in the Crankshaft for debris, damage or excessive movement.
Is there any debris, damage or excessive movement?ENGINE -2.0L and
2.4L I-4 DOHC
Ye s®Repair as necessary.
Perform Powertrain Verification Test VER-2A.
No®Go To 8
8 If there are no potential causes remaining, the CKP Sensor is assumed to be
defective.
View repair options.ENGINE -2.0L and
2.4L I-4 DOHC
Repair
Replace the CKP Sensor.
Perform Verification Test VER-2A.
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DRIVEABILITY
P-1398 MISFIRE ADAPTIVE NUMERATOR AT LIMIT ÐContinued
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TEST ACTION APPLICABILITY
2 Ignition on, engine not running
With the DRB, read DTCs and Freeze Frame Data and record.
With the DRB, Clear DTCs.
Start the engine and allow the engine to idle.
With the DRB, perform the LDP Monitor test.
Wiggle the wiring harness and connectors from the LDP connector to the PCM
connector while the monitor is running.
Note: Be careful of the engine's moving parts.
With the DRB, Read DTCs.
Does the P-1494 Leak Detection Pump Sw or Mechanical Fault DTC return during
the wiggle test?All
Ye s®Repair the wiring harness or connector as necessary.
Perform Powertrain Verification Test VER-5A.
No®Go To 3
3 Ignition Off
Using the schematic as a guide, inspect the Wiring and Connectors.
Were any problems found?All
Ye s®Repair as necessary.
Perform Powertrain Verification Test VER-5A.
No®Test Complete.
4 Ignition Off
Disconnect the LDP Connector.
Note: Check connectors - Clean/repair as necessary.
Engine off, key on.
Using a voltmeter, probe the Fused Ignition Switch Output Circuit.
Is the voltage above 10.0 volts?All
Ye s®Go To 5
No®Repair the open Fused Ignition Switch Output Circuit.
Perform Powertrain Verification Test VER-5A.
5 Ignition Off
Disconnect the Engine Vacuum Supply Hose at the LDP.
Install a Vacuum Gauge to Engine Vacuum Supply Hose at the LDP.
Start engine and read Vacuum Gauge.
Does Vacuum Gauge read within 1 inch of engine vacuum?All
Ye s®Go To 6
No®Repair leak or obstruction in Vacuum Hose.
Perform Powertrain Verification Test VER-5A.
207
DRIVEABILITY
P-1494 LEAK DETECTION PUMP PRESSURE SWITCH ÐContinued
ProCarManuals.com
TEST ACTION APPLICABILITY
6 Ignition Off
Disconnect the LDP Connector.
Note: Check connectors - Clean/repair as necessary.
Disconnect the PCM.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the resistance of the LDP Pressure Switch Sense
Circuit from the PCM Connector to a good ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair the LDP Pressure Switch Sense Circuit for a short to
ground.
Perform Powertrain Verification Test VER-5A.
No®Go To 7
7 Ignition Off
Disconnect the LDP Connector.
Note: Check connectors - Clean/repair as necessary.
Disconnect the PCM.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the resistance of the LDP Pressure Switch Sense
Circuit from the PCM Connector to the LDP Connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 8
No®Repair the open LDP Switch Sense Circuit.
Perform Powertrain Verification Test VER-5A.
8 Ignition Off
Disconnect the Engine Vacuum Supply Hose at the LDP.
Disconnect the PCM.
Note: Check connectors - Clean/repair as necessary.
Key on.
With voltmeter connected to LDP switch sense circuit at PCM connector, ground the
LDP solenoid control circuit. Then while applying vacuum to LDP with a hand
vacuum pump, observe voltmeter.
Did the voltage change?All
Ye s®Go To 9
No®Replace the LDP.
Perform Powertrain Verification Test VER-5A.
9 Ignition Off
If there are no potential causes remaining, the PCM is assumed to be defective.
View repair options.All
Repair
Replace the PCM.
Perform Powertrain Verification Test VER-5A.
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DRIVEABILITY
P-1494 LEAK DETECTION PUMP PRESSURE SWITCH ÐContinued
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Symptom:
P-1496 5 VOLT SUPPLY OUTPUT TOO LOW
When Monitored and Set Condition:
P-1496 5 VOLT SUPPLY OUTPUT TOO LOW
When Monitored: With the ignition on.
Set Condition: The 5-volt supply to the sensors is below 3.5 volts for 4 seconds.
POSSIBLE CAUSES
5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
5-VOLT SUPPLY WIRING HARNESS INTER DEF
A/C PRESSURE SENSOR DEFECTIVE
MAP SENSOR DEFECTIVE
THROTTLE POSITION SENSOR DEFECTIVE
PCM DEF (5 VOLT SUPPLY CIRCUIT)
TEST ACTION APPLICABILITY
1 Ignition On, Engine Not Running
Disconnect the Throttle Position Sensor Connector.
Note: Check connectors - Clean/repair as necessary
With a voltmeter, probe the 5-Volt Supply Ckt at the TP Sensor harness connector.
Note: Reconnect TPS Connector after measurement.
Is the voltage reading below 4.5 volts?All
Ye s®Go To 2
No®Go To 6
2 Ignition On, Engine Not Running.
Disconnect the Throttle Position Sensor Connector.
Disconnect the A/C Pressure Sensor.
Note: Check connectors - Clean/repair as necessary.
With a voltmeter, probe the TP Sensor 5-Volt Supply Circuit to the TP Sensor.
Is the 5-Volt Supply Circuit voltage above 4.0 volts?All
Ye s®Replace the A/C Pressure Sensor.
Perform Powertrain Verificaton Test VER-2A.
No®Go To 3
3 Ignition On, Engine Not Running
Disconnect the Throttle Position Sensor Connector.
Disconnect the MAP Sensor Electrical Connector.
Note: Check connectors - Clean/repair as necessary.
With the voltmeter, probe the TP Sensor 5-Volt Supply Circuit to the TP Sensor.
Is the 5-Volt Supply Circuit voltage above 4.0 volts?All
Ye s®Replace the Map Sensor.
Perform Powertrain Verification Test VER-2A.
No®Go To 4
212
DRIVEABILITY
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TEST ACTION APPLICABILITY
4 Ignition Off
Disconnect the Throttle Position Sensor Connector.
Disconnect the MAP Sensor Electrical Connector.
Disconnect the A/C Sensor Connector.
Disconnect the Powertrain Control Module Connector.
Note: Check connectors - Clean/repair as necessary.
With the ohmmeter, probe the 5-volt supply circuit at the TPS Connector.
Is the resistance below 5.0 ohms?All
Ye s®Repair the 5-volt Supply Circuit for a short to ground.
Perform Powertrain Verification Test VER-2A.
No®Go To 5
5 If there are no potential causes remaining, the Powertrain Control Module is
assumed to be defective.
View repair options.All
Repair
Replace the PCM.
Perform Powertrain Verification Test VER-2A.
6 Ignition On, Engine Not Running
Disconnect the MAP Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
With the voltmeter, probe the 5-Volt Supply Ckt at the MAP Sensor Connector.
Is the voltage reading below 4.5 volts?All
Ye s®Replace the TPS.
Perform Powertrain Verification Test VER-2A.
No®Test Complete.
7 Ignition On, Engine Not Running
Disconnect the MAP Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
With the DRB in voltmeter mode, probe the 5-volt supply circuit voltage at the MAP
Sensor Connector.
Wiggle all connectors and wiring to all sensors (MAP, A/C PRESS, TPS).
While you wiggle the connectors and wiring to all sensors monitor the 5.0 volt supply
circuit voltage.
Was there any voltage change?All
Ye s®Repair the harness or connector that caused the voltage change.
Perform Powertrain Verification Test VER-2A.
No®Test Complete.
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P-1496 5 VOLT SUPPLY OUTPUT TOO LOW ÐContinued
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Symptom:
P-1598 A/C PRESSURE SENSOR VOLTS TOO HIGH
When Monitored and Set Condition:
P-1598 A/C PRESSURE SENSOR VOLTS TOO HIGH
When Monitored: With the ignition on, the engine running, and the A/C relay energized.
Set Condition: The A/C pressure sensor signal at PCM cavity 42 goes above 4.9 volts.
POSSIBLE CAUSES
AIR CONDITIONING PRESSURE SENSOR GROUND CIRCUIT OPEN
AIR CONDITIONING PRESSURE SENSOR DEFECTIVE
A/C PRESS SENSOR CONN AND WIRING HARN INTER DAMAGE
A/C PRESSURE SENSOR CONNECTOR AND HARNESS OBSERVABLE DEFECT
A/C PRESSURE SENSOR SIGNAL CIRCUIT OPEN
A/C PRESSURE SENSOR SIGNAL SHORT TO VOLTAGE
PCM DEFECTIVE
TEST ACTION APPLICABILITY
1 Ignition On, Engine Not Running
With the DRB, read the A/C Pressure Sensor voltage.
Is the A/C Pressure Sensor voltage above 4.6 volts?All
Ye s®Go To 2
No®Go To 7
2 Ignition Off
Disconnect the A/C Pressure Sensor.
Note: Check connectors - Clean/repair as necessary.
Turn ignition on.
Using a Voltmeter, measure voltage of the A/C Pressure Signal Circuit to ground.
Is the voltage above 6.0 volts?All
Ye s®Repair A/C Pressure Sensor Signal shorted to voltage.
Perform Powertrain Verification Test VER-2A.
No®Go To 3
214
DRIVEABILITY
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TEST ACTION APPLICABILITY
3 Ignition Off
Disconnect the A/C Pressure Sensor.
Note: Check connectors - Clean/repair as necessary.
Connect a Jumper Wire between the A/C Pressure Sensor Signal Circuit and Sensor
Ground Circuit.
Ignition on with engine not running.
With the DRB, read the A/C Pressure Sensor voltage.
Is the voltage below 1.0 volt?All
Ye s®Replace the A/C Pressure Sensor.
Perform Powertrain Verification Test VER-2A.
No®Go To 4
4 Ignition Off
Disconnect the A/C Sensor Electrical Connector.
Note: Check connectors - Clean/repair as necessary.
Connect a Jumper Wire between the A/C Pressure Sensor Signal Circuit and Engine
Ground.
Ignition on, engine not running.
With the the DRB, read the A/C Pressure Sensor voltage.
Is the voltage below 1.0 volt?All
Ye s®Repair the open Sensor Ground Circuit.
Perform Powertrain Verification Test VER-2A.
No®Go To 5
5 Ignition Off.
Disconnect the A/C Pressure Sensor.
Note: Check connectors - Clean/repair as necessary.
Disconnect the PCM.
Using an Ohmmeter, measure the A/C Pressure Sensor Signal Circuit from the PCM
to the Sensor.
Is the resistance below 5.0 ohms?All
Ye s®Go To 6
No®Repair the open A/C Presure Sensor Circuit.
Perform Powertrain Verification Test VER-2A.
6 If there are no potential causes remaining, the PCM is assumed to be defective.
View repair options.All
Repair
Replace the PCM.
Perform Powertrain Verification Test VER-2A.
7 Ignition On, Engine Not Running.
With the DRB, read the A/C Pressure Sensor voltage.
Using the schematic as a guide, wiggle the A/C Pressure Sensor Connector and
Harness.
Monitor the DRB display.
Was there any A/C Pressure Sensor voltage change?All
Ye s®Repair the Harness or Connector that caused the voltage to
change.
Perform Powertrain Verification Test VER-2A.
No®Go To 8
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DRIVEABILITY
P-1598 A/C PRESSURE SENSOR VOLTS TOO HIGH ÐContinued
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