DODGE RAM SRT-10 2006 Service Repair Manual

Theory of Operation
The engine coolant temperature sensor is a negative temperature coefficient thermistor-type sensor whose resis-
tance varies inversely with temperature. At cold temperatures the sensorresistance is high so the voltage is high.
As the coolant temperature increases the resistance decreases and the voltage becomes low.
When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts.
Set Condition:
The Engine Coolant Temperature (ECT) Signal circuit voltage at the PCM goes below 0.8 of a volt for more
than 3 seconds.
Possible Causes
(K2) ECT SIGNAL CIRCUIT SHORTED TO GROUND
(K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
ECT SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ECT SENSOR VOLTAGE BELOW 1.0 OF A VOLT
Ignition on, engine not running.
With a scan tool, read the ECT voltage.
Is the voltage below 1.0 of a volt?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Symptom. (Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING)
2.ECT SENSOR
Turn the ignition off.
Disconnect the ECT harness connector.
Ignition on, engine not running.
With a scan tool, read ECT voltage.
Is the voltage above 1.0 volt?
Ye s>>
Replace the ECT Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3

3.(K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
Turn the ignition off.
Disconnect the C1 PCM harness connector.
Measure the resistance between the (K900) Sensor ground circuit and
the (K2) ECT Signal circuit in the ECT Sensor harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the short to between the (K900) Sensor ground cir-
cuit and the (K2) ECT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(K2) ECT SIGNAL CIRCUIT SHORTED GROUND
Measure the resistance between ground and the (K2) ECT Signal circuit
in the ECT Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (K2) ECT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5

5.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.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

P0118-ENGINE COOLANT TEMP SENSOR VOLTAGE TOO HIGH
For a complete wiring diagramRefer to Section 8W.

When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts.
Set Condition:
The Engine Coolant Temperature (ECT) sensor circuit voltage at the PCM is greater than 4.94 volts for more
than 3.0 seconds.
Possible Causes
(K2) ECT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(K2) ECT SIGNAL CIRCUIT OPEN
(K900) SENSOR GROUND CIRCUIT OPEN
ECT SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ECT SENSOR VOLTAGE ABOVE 4.94 VOLTS
Ignition on, engine not running.
With a scan tool, read the ECT voltage.
Is the voltage above 4.94 volts?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Symptom. (Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING)
2.ECT SENSOR
Turn the ignition off.
Disconnect the ECT harness connector.
Connect a jumper wire between the (K2) ECT Signal circuit and the
(K900) Sensor ground circuit in the ECT harness connector.
Ignition on, engine not running.
With a scan tool, read ECT voltage.
Is the voltage below 1.0 volt with the jumper wire installed?
Ye s>>
Replace the ECT Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
NOTE: Remove the jumper wire before continuing.

3.(K2) ECT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the C1 PCM harness connector.
Ignition on, engine not running.
Measure the voltage on the (K2) ECT Signal circuit in the ECT Sensor
harness connector.
Is the voltage above 0 volts?
Ye s>>
Repair the short to battery voltage in the (K2) ECT Signal
circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(K2) ECT SIGNAL CIRCUIT OPEN
Turn the ignition off.
Measure the resistance of the (K2) ECT Signal circuit from the ECT
Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 5
No>>
Repair the open in the (K2) ECT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)

5.(K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor ground circuit from the
ECT Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 6
No>>
Repair the open in the (K900) Sensor ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
6.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.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

P0121-TP SENSOR VOLTAGE DOES NOT AGREE WITH MAP
For a complete wiring diagramRefer to Section 8W.

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)

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)