Dodge Ram Truck 1500-2500-3500. Manual — part 1158

P0121-TP SENSOR VOLTAGE DOES NOT AGREE WITH MAP (CONTINUED)

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?

Yes

>> 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)

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

Yes

>> 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.

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ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

DR/DH

P0121-TP SENSOR VOLTAGE DOES NOT AGREE WITH MAP (CONTINUED)

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?

Yes

>> 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)

14.

SHORT TO GROUND IN THE (K1) MAP SENSOR SIGNAL CIRCUIT

Measure the resistance between ground and the (K1) MAP Sensor
Signal circuit at the MAP Sensor harness connector.

Is the resistance below 100 ohms?

Yes

>> 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)

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

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P0121-TP SENSOR VOLTAGE DOES NOT AGREE WITH MAP (CONTINUED)

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?

Yes

>> 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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ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

DR/DH

P0122-THROTTLE POSITION SENSOR #1 VOLTAGE TOO LOW

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

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