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When Monitored:
With the engine running and no MAP Sensor or TP Sensor DTC’s set. Engine speed must be greater than
1600 RPM.
Set Condition:
The PCM performs two separate tests. When the manifold vacuum is high, the TP Sensor should be low.
When the manifold vacuum is low, the TP Sensor signal should be high. If the proper TP Sensor voltage is not
detected when the two conditions are met, a DTC will be set after 4 seconds.
Possible Causes
RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
MAP SENSOR
RESISTANCE IN THE (K1) MAP SENSOR SIGNAL CIRCUIT
(K1) MAP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
TP SENSOR OPERATION
RESISTANCE IN THE TP SENSOR (F855) 5-VOLT SUPPLY
TP SENSOR (F855) 5-VOLT SUPPLY SHORTED TO GROUND
THROTTLE POSITION SENSOR
RESISTANCE IN THE (K22) TP SENSOR NO.1 SIGNAL CIRCUIT
RESISTANCE BETWEEN GROUND AND THE (K22) TP SENSOR NO.1 SIGNAL CIRCUIT
RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.GOOD TRIP EQUAL TO ZERO
NOTE: Diagnose any TP Sensor or MAP component DTCs first before continuing.
NOTE: If the P0500 - No Vehicle Speed Signal is set along with this DTC, referto the P0500 diagnostics
before continuing.
NOTE: The throttle plate and linkage should be free of binding and carbon build up.
NOTE: Make sure the throttle plate is at the idle position.
Ignition on, engine not running.
NOTE: Repair any vacuum leaks that are present before continuing.
With the scan tool, read DTCs and record the related Freeze Frame data.
Is the Good Trip Counter displayed and equal to zero?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
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2.MAP SENSOR OPERATION
Start the engine.
With the scan tool, monitor the MAP Sensor voltage.
Snap the throttle.
Does the scan tool display MAP voltage from below 2.0 volts at idle to above 3.5 volts at WOT?
Ye s>>
Go To 3
No>>
Go To 10
3.TP SENSOR OPERATION
Ignition on, engine not running.
With the scan tool, monitor the TP Sensor voltage while slowly depressing the throttle pedal from the idle position
to the wide open throttle position.
Does voltage start at approximately 0.8 of a volt and go above 3.5 volts witha smooth transition?
Ye s>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT
Turn the ignition off.
Disconnect the TP Sensor harness connector.
Disconnect the PCM harness connectors.
Measure the resistance of the (F855) 5-volt Supply circuit from the TP
Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 5
No>>
Repair the excessive resistance in the (F855) 5-volt Supply
circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
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5.TP SENSOR (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (F855) 5-volt Supply
circuit at the TP Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (F855) 5-volt Supply cir-
cuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
6.THROTTLE POSITION SENSOR
Connect the PCM harness connectors.
With the scan tool, monitor the TP Sensor voltage.
Ignition on, engine not running.
Connect a jumper wire between the (K22) TP Sensor No.1 Signal circuit
and the (K900) Sensor ground circuit.
Did the TP Sensor voltage change from approximately 4.9 volts
to below 0.5 of a volt with the jumper
Ye s>>
ReplacetheThrottlePositionSensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 7
NOTE: Remove the jumper wire before continuing.
7.RESISTANCE IN THE (K22) TP SENSOR SIGNAL CIRCUIT
Turn the ignition off.
Disconnect the PCM harness connectors.
Measure the resistance of the (K22) TP Sensor No.1 Signal circuit from
the TP Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 8
No>>
Repair the excessive resistance in the (K22) TP Sensor
No.1 Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
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8.(K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (K22) TP Sensor No.1
Signal circuit at the TP Sensor harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the short to ground in the (K22) TP Sensor No.1
Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 9
9.RESISTANCE IN (K900) SENSOR GROUND CIRCUIT
Measure the resistance of the (K900) Sensor ground circuit from the TP
Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 16
No>>
Repair the excessive resistance in the (K900) Sensor
ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
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10.EXCESSIVE RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT
Turn the ignition off.
Disconnect the MAP Sensor harness connector.
Disconnect the PCM harness connectors.
Measure the resistance of the (F855) 5-volt Supply circuit from the MAP
Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 11
No>>
Repair the excessive resistance in the (F855) 5-volt Supply
circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
11 .MAP (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (F855) 5-volt Supply
circuit at the MAP Sensor harness connector.
Is the resistance above 100k ohms?
Ye s>>
Go To 12
No>>
Repair the short to ground in the (F855) 5-volt Supply cir-
cuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
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12.MAP SENSOR
Connect the PCM harness connectors.
Ignition on, engine not running.
With the scan tool, monitor the MAP Sensor voltage.
Connect a jumper wire between the (K1) MAP Sensor Signal circuit and
the (K900) Sensor ground circuit.
Cycle the ignition switch from off to on.
Did the voltage change from approximately 4.9 volts to below
0.5 of a volt with the jumper wire inst
Ye s>>
Replace the MAP Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 13
NOTE: Remove the jumper wire before continuing.
13.EXCESSIVE RESISTANCE IN THE (K1) MAP SENSOR SIGNAL CIRCUIT
Turn the ignition off.
Disconnect the PCM harness connectors.
Measure the resistance of the (K1) MAP Sensor Signal circuit from the
MAP Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 14
No>>
Repair the excessive resistance in the (K1) MAP Sensor
Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
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14.SHORT TO GROUND IN THE (K1) MAP SENSOR SIGNAL CIRCUIT
Measure the resistance between ground and the (K1) MAP Sensor Sig-
nal circuit at the MAP Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Go To 15
No>>
Repair the short to ground in the (K1) MAP Sensor Signal
circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
15.RESISTANCE IN MAP (K900) SENSOR GROUND CIRCUIT
Measure the resistance of the (K900) Sensor ground circuit from the
MAP Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 16
No>>
Repair the excessive resistance in the (K900) Sensor
ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
16.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.
If there are no possible causes remaining, view repair.
Repair
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
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P0122-THROTTLE POSITION SENSOR #1 VOLTAGE TOO LOW
For a complete wiring diagramRefer to Section 8W.