Symptom:
P-1297 NO CHANGE IN MAP FROM START TO RUN
When Monitored and Set Condition:
P-1297 NO CHANGE IN MAP FROM START TO RUN
When Monitored: Engine is idling with a stable RPM (RPM fluctuation < 64 RPM) and
the vehicle is not moving.
Set Condition: Too small a difference is seen between barometric pressure at ignition on
and manifold vacuum.
POSSIBLE CAUSES
MAP SENSOR 5-VOLT SUPPLY CIRCUIT OPEN
MAP SENSOR WIRING HARNESS INTERMITTENT DEF
VACUUM PORTS RESTRICTED OR DEFECTIVE
MANIFOLD ABSOLUTE PRESSURE SENSOR RESTRICTED
MAP SENSOR DEFECTIVE (A)
MAP SENSOR DEFECTIVE (B)
TEST ACTION APPLICABILITY
1 Ignition On, Engine Not Running
With the DRB, read codes
Is9MAP Sensor voltage too low9code set?All
Ye s®Refer to symptom P-0107 MAP SENSOR VOLTAGE TOO LOW in
the DRIVEABILITY category.
No®Go To 2
2 With the DRB erase Codes.
Ignition On, Engine Not Running
Start engine and allow engine to idle for 30 seconds.
With the DRB read codes.
Does the DRB show9No change in MAP from start to run9?All
Ye s®Go To 3
No®Go To 6
3 Ignition on, with engine not running.
Disconnect MAP Sensor.
Note:Check connectors - clean/repair as necessary.
Ignition on, with engine not running.
Using a Voltmeter, measure the MAP Sensor 5-Volt Supply Circuit at the MAP
Sensor Connector.
Is the voltage above 4.0 volts?All
Ye s®Go To 4
No®Repair the open MAP Sensor 5-volt Supply Circuit.
Perform Powertrain Verification Test VER-5A.
183
DRIVEABILITY
ProCarManuals.com
TEST ACTION APPLICABILITY
4 Ignition off.
Remove MAP Sensor and inspect for Vacuum restrictions.
Check connectors - Clean/repair as necessary.
Was there a restriction?All
Ye s®Remove the restriction and reinstall the MAP Sensor
Perform Powertrain Verification Test VER-5A.
No®Go To 5
5 If there are no potential causes remaining, the MAP Sensor is assumed to be
defective.
View repair options.All
Repair
Replace the MAP Sensor.
Perform Powertrain Verification Test VER-5A.
6 Engine must be running.
While monitoring the DRB display, snap the Throttle open and closed.
Did the vacuum drop rapidly below 1.09?All
Ye s®Go To 7
No®Go To 8
7 Engine must be running.
With the DRB,set the engine speed to 1500 RPM.
With the engine RPM at 1500, read MAP sensor voltage.
While monitoring the voltage, wiggle the wiring from the MAP Sensor to PCM.
Did the engine stall or voltage become erratic?All
Ye s®Repair the Wiring or Connector defective between the Map
Sensor and the PCM.
Perform Powertrain Verification Test VER-5A.
No®Test Complete.
8 Engine must be running.
With the DRB,set the engine speed to 1500 RPM.
With the engine RPM at 1500, read MAP sensor voltage.
While monitoring the voltage, wiggle the wiring from the MAP Sensor to PCM.
Did the engine stall or voltage become erratic?All
Ye s®Repair the Wiring or Connector defective between the Map
Sensor and the PCM.
Perform Powertrain Verification Test VER-5A.
No®Go To 9
9 Ignition Off
Remove the MAP Sensor and inspect condition of Intake Manifold and MAP Sensor
Vacuum Ports.
Check connectors - Clean/repair as necessary.
Is there a restriction or defect in the Vacuum Ports?All
Ye s®Repair the restricted or defective Vacuum Ports.
Perform Powertrain Verification Test VER-5A.
No®Go To 10
184
DRIVEABILITY
P-1297 NO CHANGE IN MAP FROM START TO RUN ÐContinued
ProCarManuals.com
TEST ACTION APPLICABILITY
10 If there are no potential causes remaining, the MAP Sensor is assumed to be
defective.
View repair options.All
Repair
Replace the MAP sensor.
Perform Powertrain Verification Test VER-5A.
185
DRIVEABILITY
P-1297 NO CHANGE IN MAP FROM START TO RUN ÐContinued
ProCarManuals.com
Symptom:
P-1391 INTERMITTENT LOSS OF CMP OR CKP
When Monitored and Set Condition:
P-1391 INTERMITTENT LOSS OF CMP OR CKP
When Monitored: Engine running over 7 seconds.
Set Condition: When the expected cam signal level disagrees with the actual cam signal
level.
POSSIBLE CAUSES
CKP SENSOR CKT WIRING HARNESS INTER DEF
CMP SENSOR SIGNAL CKT WIRING HARNESS INTER DEF
CAMSHAFT POSITION SENSOR DEFECTIVE
CAMSHAFT SPROCKET DEFECTIVE
CRANKSHAFT DEFECTIVE
CRANKSHAFT POSITION SENSOR DEFECTIVE
DISTRIBUTOR PULSE RING DEFECTIVE
FLYWHEEL DEFECTIVE
CAMSHAFT TARGET MAGNET DEFECTIVE
CAMSHAFT THRUST PLATES(S) NOT ATTACHED
CKP SENSOR CONNECTOR TERMINALS OBS DEF
CKP SENSOR CONNECTOR TERMINALS OBS DEFECT
PCM CONN TERMINALS OBS DEF (CKP SENSOR)
PCM CONN TERMINALS OBS DEF (CMP SENSOR)
CAMSHAFT/CYLINDER HEAD DEFECTIVE
TEST ACTION APPLICABILITY
1 Ignition Off.
At the CMP Sensor, backprobe the CMP Sensor Signal Circuit with the Oscilloscope
voltage measurement lead.
Start the Engine and observe the CMP Sensor voltage pattern on the Oscilloscope.
Are there any of the Camshaft Position Sensor Signals missing?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Go To 2
No®Go To 6
191
DRIVEABILITY
ProCarManuals.com
TEST ACTION APPLICABILITY
2 Ignition Off.
Disconnect the CMP Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Inspect all Terminals.
Is any Terminal damaged, pushed out or miswired?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Repair Terminal(s) for damage, pushout or miswiring.
Perform Powertrain Verification Test VER-5A.
No®Go To 3
3 Ignition Off.
Disconnect the PCM.
Note: Check connectors - Clean/repair as necessary.
Inspect all Terminals.
Is any Terminal damaged, pushed out, or miswired?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Repair Terminal(s) for damage, pushout or miswiring.
Perform Powertrain Verification Test VER-5A.
No®Go To 4
4 Ignition Off.
Disconnect the CMP Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Remove the Camshaft Position Sensor.
Inspect the Camshaft Sprocket. See pertinent service information for instructions.
Is the Camshaft Sprocket okay?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Go To 5
No®Repair as necessary.
Perform Powertrain Verification Test VER-5A.
5 Ignition Off.
Disconnect the CMP Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Remove the CMP Sensor.
Inspect the Camshaft Thrust Plate(s).
Are the Camshaft Thrust Plate(s) attached?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Replace the Camshaft Position Sensor.
Perform Powertrain Verification Test VER-5A.
No®Repair or replace the Camshaft Thrust Plate(s) as necessary.
Perform Powertrain Verification Test VER-5A.
6 Start Engine.
At PCM, backprobe CMP Sensor Signal Circuit with Oscilloscope's voltage measure-
ment lead.
While observing the Oscilloscope pattern, wiggle CMP Sensor Circuit from Sensor to
PCM.
Were any signals missing when the wiggle test was conducted?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Note where wiggling the Wires caused a missing CMP Sensor
Signal. Repair Camshaft and Crankshaft Wiring Harness as
necessary.
Perform Powertrain Verification Test VER-5A.
No®Go To 7
192
DRIVEABILITY
P-1391 INTERMITTENT LOSS OF CMP OR CKP ÐContinued
ProCarManuals.com
TEST ACTION APPLICABILITY
7 Ignition Off.
At the CKP Sensor, backprobe the CKP Sensor Signal Circuit with the Oscilloscope's
voltage measurement lead.
Start the Engine and observe the CKP Sensor voltage pattern on the Oscilloscope.
Are any Crankshaft Position Sensor Signals missing?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Go To 8
No®Go To 11
8 Ignition Off.
Disconnect the CKP Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Inspect all Terminals.
Is any Terminal damaged, pushed out or miswired?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Repair Terminal(s) for damage, pushout or miswiring.
Perform Powertrain Verification Test VER-5A.
No®Go To 9
9 Ignition Off.
Disconnect the PCM.
Note: Check connectors - Clean/repair as necessary.
Inspect all Terminals.
Is any Terminal damaged, pushed out or miswired?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Repair Terminal(s) for damage, pushout or miswiring.
Perform Powertrain Verification Test VER-5A.
No®Go To 10
10 Ignition Off
Remove the Crankshaft Position (CKP) Sensor.
Inspect the Slots in the Flywheel for debris or damage.
Is the Flywheel damaged?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Repair or replace as necessary.
Perform Powertrain Verification Test VER-5A.
No®Replace the Crankshaft Position Sensor.
Perform Powertrain Verification Test VER-5A.
11 Start Engine.
At PCM, backprobe CKP Sensor Signal Circuit with Oscilloscope's voltage measure-
ment lead.
While observing the Oscilloscope pattern, wiggle CKP Sensor Circuit from Sensor to
PCM.
Were any CKP Sensor Signals missing when the wiggle test was conducted?ENGINE - 3.3L V6
and/or ENGINE -
3.8L V6 and/or EN-
GINE - 3.3L V6
FFV
Ye s®Note where wiggling the wires caused a missing CKP Sensor
signal. Repair Camshaft and Crankshaft Wire Harness as neces-
sary.
Perform Powertrain Verification Test VER-5A.
No®Test Complete.
193
DRIVEABILITY
P-1391 INTERMITTENT LOSS OF CMP OR CKP ÐContinued
ProCarManuals.com
TEST ACTION APPLICABILITY
12 Ignition Off.
At the CMP Sensor, backprobe the CMP Sensor Signal Circuit with the Oscilloscope
voltage measurement lead.
Start the Engine and observe the CMP Sensor voltage pattern on the Oscilloscope.
Are there any of the Camshaft Position Sensor Signals missing?ENGINE - 3.0L V6
Ye s®Go To 13
No®Go To 16
13 Ignition Off.
Disconnect the CMP Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Inspect all Terminals.
Is any Terminal damaged, pushed out or miswired?ENGINE - 3.0L V6
Ye s®Repair Terminal(s) for damage, pushout or miswiring.
Perform Powertrain Verification Test VER-5A.
No®Go To 14
14 Ignition Off.
Disconnect the PCM.
Note: Check connectors - Clean/repair as necessary.
Inspect all Terminals.
Is any Terminal damaged, pushed out, or miswired?ENGINE - 3.0L V6
Ye s®Repair Terminal(s) for damage, pushout or miswiring.
Perform Powertrain Verification Test VER-5A.
No®Go To 15
15 Ignition Off.
Remove Distributor Cap and Rotor.
Inspect the Pulse Ring for damage or misalignment.
Is the Pulse Ring okay?ENGINE - 3.0L V6
Ye s®Replace the Camshaft Position Sensor.
Perform Powertrain Verification Test VER-5A.
No®Repair or replace the Distributor Pulse Ring as necessary.
Perform Powertrain Verification Test VER-5A.
16 Start Engine.
At PCM, backprobe CMP Sensor Signal Circuit with Oscilloscope's voltage measure-
ment lead.
While observing the Oscilloscope pattern, wiggle CMP Sensor Circuit from Sensor to
PCM.
Were any signals missing when the wiggle test was conducted?ENGINE - 3.0L V6
Ye s®Note where wiggling the Wires caused a missing CMP Sensor
Signal. Repair Camshaft and Crankshaft Wiring Harness as
necessary.
Perform Powertrain Verification Test VER-5A.
No®Go To 17
194
DRIVEABILITY
P-1391 INTERMITTENT LOSS OF CMP OR CKP ÐContinued
ProCarManuals.com
TEST ACTION APPLICABILITY
17 Ignition Off.
At the CKP Sensor, backprobe the CKP Sensor Signal Circuit with the Oscilloscope's
voltage measurement lead.
Start the Engine and observe the CKP Sensor voltage pattern on the Oscilloscope.
Are any Crankshaft Position Sensor Signals missing?ENGINE - 3.0L V6
Ye s®Go To 18
No®Go To 21
18 Ignition Off.
Disconnect the CKP Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Inspect all Terminals.
Is any Terminal damaged, pushed out or miswired?ENGINE - 3.0L V6
Ye s®Repair Terminal(s) for damage, pushout or miswiring.
Perform Powertrain Verification Test VER-5A.
No®Go To 19
19 Ignition Off.
Disconnect the PCM.
Note: Check connectors - Clean/repair as necessary.
Inspect all Terminals.
Is any Terminal damaged, pushed out or miswired?ENGINE - 3.0L V6
Ye s®Repair Terminal(s) for damage, pushout or miswiring.
Perform Powertrain Verification Test VER-5A.
No®Go To 20
20 Ignition Off.
Remove the Crankshaft Position (CKP) Sensor.
Inspect the Slots in the Flywheel for debris or damage.
Is the Flywheel damaged?ENGINE - 3.0L V6
Ye s®Repair or replace as necessary.
Perform Powertrain Verification Test VER-5A.
No®Replace the Crankshaft Position Sensor.
Perform Powertrain Verification Test VER-5A.
21 Start Engine.
At PCM, backprobe CKP Sensor Signal Circuit with Oscilloscope's voltage measure-
ment lead.
While observing the Oscilloscope pattern, wiggle CKP Sensor Circuit from Sensor to
PCM.
Were any CKP Sensor Signals missing when the wiggle test was conducted?ENGINE - 3.0L V6
Ye s®Note where wiggling the wires caused a missing CKP Sensor
signal. Repair Camshaft and Crankshaft Wire Harness as neces-
sary.
Perform Powertrain Verification Test VER-5A.
No®Test Complete.
195
DRIVEABILITY
P-1391 INTERMITTENT LOSS OF CMP OR CKP ÐContinued
ProCarManuals.com