Dodge Ram Truck 1500-2500-3500. Manual — part 1254

P1296-NO 5-VOLTS TO MAP SENSOR

9 - 1938

ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

DR/DH

P1296-NO 5-VOLTS TO MAP SENSOR (CONTINUED)

For the Engine circuit diagram (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CON-
TROL MODULE - SCHEMATIC - ELECTRICAL)

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
During power-down and battery voltage greater than 10.4 volts.

•

Set Condition:
The MAP sensor signal voltage goes below 2.35 volts with the key off for 5 seconds.

Possible Causes

MAP SENSOR VOLTS BELOW 2.3 VOLTS

MAP SENSOR

(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND

SHORTED SENSOR

(F855) 5-VOLT SUPPLY CIRCUIT OPEN

PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)

1.

MAP SENSOR VOLTS BELOW 2.3 VOLTS

NOTE: If the P0107 - MAP Sensor Voltage Too Low is also set, diagnose it first before continuing with P1296
- No 5-volts To MAP Sensor.
Ignition on, engine not running.

With the scan tool, read DTCs and record the related Freeze Frame data.

With the scan tool in Sensors, read the MAP Sensor voltage.

Is the voltage below 2.35 volts?

Yes

>> Go To 2

No

>> Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure).

Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

2.

(F855) 5-VOLT SUPPLY CIRCUIT

Turn the ignition off.

Disconnect the MAP Sensor harness connector.

Ignition on, engine not running.

Measure the voltage on the (F855) 5-volt Supply circuit at the MAP
Sensor harness connector.

Is the voltage above 4.5 volts?

Yes

>> Go To 3

No

>> Go To 4

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

9 - 1939

P1296-NO 5-VOLTS TO MAP SENSOR (CONTINUED)

3.

MAP SENSOR

With the scan tool in Sensors, read the MAP Sensor voltage with the Sensor harness connector disconnected.

Is the voltage above 4.5 volts?

Yes

>> Replace the MAP Sensor.

Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

No

>> Go To 7

4.

SHORTED SENSOR

Measure the voltage on the (K7) 5-volt Supply circuit in the MAP Sen-
sor harness connector while disconnecting the remaining Sensors that
share the (K7) 5-volt Supply circuit.

Does the voltage return to approximately 5.0 volts with any
Sensor disconnected?

Yes

>> Replace the Sensor that pulled the (K7) 5-volt Supply cir-

cuit low.

Perform POWERTRAIN VERIFICATION TEST. (Refer to 9
- ENGINE - STANDARD PROCEDURE)

No

>> Go To 5

9 - 1940

ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

DR/DH

P1296-NO 5-VOLTS TO MAP SENSOR (CONTINUED)

5.

(F855) 5-VOLT SUPPLY CIRCUIT OPEN

Turn the ignition off.

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?

Yes

>> Go To 6

No

>> Repair the excessive resistance in the (F855) 5-volt Sup-

ply circuit.

Perform POWERTRAIN VERIFICATION TEST. (Refer to 9
- ENGINE - STANDARD PROCEDURE)

6.

(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (F855) 5-volt Supply
circuit in the MAP Sensor harness connector.

Is the resistance below 100 ohms?

Yes

>> Repair the short to ground in the (F855) 5-volt Supply cir-

cuit.

Perform POWERTRAIN VERIFICATION TEST. (Refer to 9
- ENGINE - STANDARD PROCEDURE)

No

>> Go To 7

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

9 - 1941