ignition 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. The INSUFFICIENT
COOLANT TEMP FOR CLOSED-LOOP FUEL CONTROL determines if the engine coolant temperature will reach
theclosedloopfuelingcontroltemperaturelimitinaregulatedtimeafterstart.
When Monitored:
With battery voltage greater than 10.4 volts and after engine is started.
Set Condition:
The engine temperature does not go above -10°C (15°F). Failure time depends on start-up coolant tempera-
ture and ambient temperature. (i.e. 2 minutes for a start temp of -10°C (15°F) or up to 10 minutes for a vehicle
with a start-up temp of -28°C (5°F). Two Trip Fault. Three good trips to turnoff the MIL.
Possible Causes
LOW COOLANT LEVEL
THERMOSTAT
ECT SENSOR
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.CHECKING COOLANT LEVEL AND CONDITION
Ignition on, engine not running.
With a scan tool, read DTCs.
NOTE: If an Engine Coolant Temperature (ECT) DTC is set along with this code, diagnose the ECT DTC first.
NOTE: Inspect the ECT terminals and related PCM terminals. Make sure the terminals are free from corro-
sion and damage.
NOTE: The best way to diagnose this DTC is to allow the vehicle to sit overnight outside in order to have
a totally cold soaked engine.
NOTE: Extremely cold outside ambient temperatures may have caused this DTCtoset.
WARNING: Never open the cooling system when the engine is hot. The system isunder pressure. Extreme
burns or scalding may result. Failure to follow these instructions can result in personal injury or death.
Allow the engine to cool before opening the cooling system.
Inspect the coolant system for proper level and condition.
Is the coolant level and condition OK?
Ye s>>
Go To 2
No>>
Inspect the vehicle for a coolant leak, make the appropriate repairs, and add the correct amount of
coolant.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

2.THERMOSTAT OPERATION
NOTE: This test works best if performed on a cold engine (cold soak)
Ignition on, engine not running.
With a scan tool, read the Eng Coolant Tmp Deg value. If the engine was allowed to sit overnight (cold soak), the
temperature value should be a sensible value that is somewhere close to theambient temperature.
NOTE: If engine coolant temperature is above 82°C (180°F), allow the engine to cool until 65°C (150°F) is
reached.
Start the Engine.
During engine warm-up monitor the Eng Coolant Tmp Deg value. The temp deg value change should be a smooth
transition from start up to normal operating temp 82°C (180°F). Also monitor the actual coolant temperature with a
thermometer.
NOTE: As the engine warms up to operating temperature, the actual coolant temperature (thermometer read-
ing) and the scan tool Eng Coolant Tmp Deg values should stay relatively close to each other.
Using the appropriate service information, determine the proper openingtemperature of the thermostat.
Did the thermostat open at the proper temperature?
Ye s>>
Go To 3
No>>
Replace the thermostat.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.ECT SENSOR OPERATION
Ignition on, engine not running.
With a scan tool, read the Eng Coolant Tmp Deg value. If the engine was allowed to sit overnight (cold soak), the
temperature value should be a sensible value that is somewhere close to theambient temperature.
NOTE: If engine coolant temperature is above 82°C (180°F), allow the engine to cool until 65°C (150°F) is
reached.
Start the Engine.
During engine warm-up monitor the Eng Coolant Tmp Deg value. The temp deg value change should be a smooth
transition from start up to normal operating temp 82°C (180°F). Also monitor the actual coolant temperature with a
thermometer.
NOTE: As the engine warms up to operating temperature, the actual coolant temperature (thermometer read-
ing) and the scan tools Eng Coolant Tmp Deg value should stay relatively close to each other.
Is the thermometer reading relatively close to the scan tool ECT reading?
Ye s>>
Te s t C o m p l e t e .
No>>
Replace the Engine Coolant Temperature Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

When Monitored:
At a cold start, engine coolant below 98°F, Ambient/Battery Sensor readingwithin27°F,andEngineCoolant
Temperature above 170°F on the previous key off.
Set Condition:
The Oxygen Sensor signal voltage is below 0.156 of a volt for 28 seconds after starting engine.
Possible Causes
(K41) O2 1/1 SIGNAL CIRCUIT SHORTED TO GROUND
(K41) O2 1/1 SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
O2 SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.O2 SENSOR BELOW 0.16 OF A VOLT
Ignition on, engine not running.
With the scan tool, read DTCs and record the related Freeze Frame data.
Start the engine.
Allow the engine to idle for 4 to 5 minutes.
With the scan tool, read the O2 Sensor voltage.
Is the voltage below 0.16 of a volt?
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.O2 SENSOR OPERATION
WARNING: When the engine is operating, do not stand in a direct line with thefan. Do not put your hands
near the pulleys, belts, or fan. Do no wear loose clothing.
Disconnect the O2 Sensor harness connector.
Start the engine.
With the scan tool, monitor the O2 Sensor voltage.
IstheO2Sensorvoltageabove0.16ofavolt?
Ye s>>
Replace the O2 Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3

3.(K41) O2 SENSOR 1/1 SIGNAL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C1 PCM harness connector.
Measure the resistance between ground and the (K41) O2 Sensor 1/1
Signal circuit at the 1/1 O2 Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (K41) O2 Sensor 1/1Sig-
nal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(K41) O2 SENSOR 1/1 SIGNAL CIRCUIT SHORTED TO (K900) SENSOR GROUND CIRCUIT
Measure the resistance between the (K41) O2 Sensor 1/1 Signal circuit
and the (K900) Sensor ground circuit at the 1/1 O2 Sensor harness
connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short between the (K900) Sensor ground circuit
and the (K41) O2 Sensor 1/1 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)

When Monitored:
With battery voltage greater than 10.4 volts, engine running for more than4 minutes and coolant temperature
above 180°F.
Set Condition:
The oxygen sensor voltage is above 1.5 volts.
Possible Causes
(K41) O2 1/1 SIGNAL CIRCUIT SHORTED TO VOLTAGE
(K99) O2 SENSOR 1/1 HEATER CONTROL CIRCUIT OPEN
(K41) O2 1/1 SIGNAL CIRCUIT OPEN
(K900) SENSOR GROUND CIRCUIT OPEN
(K343) ASD RELAY OUTPUT CIRCUIT OPEN
(K41) O2 1/1 SIGNAL CIRCUIT SHORTED TO THE (K343) ASD RELAY OUTPUT CIRCUIT
O2 SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.O2 SENSOR ABOVE 1.5 VOLTS
Ignition on, engine not running.
With the scan tool, read DTCs and record the related Freeze Frame data.
Start the engine.
Allow the engine to idle for 4 to 5 minutes.
With the scan tool, read the O2 Sensor voltage.
Is the voltage above 1.5 volts?
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.(K41) O2 1/1 SIGNAL CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off.
Disconnect the C1 PCM harness connector.
Ignition on, engine not running.
Using a 12-volt test light connected to ground, probe the (K41) O2 Sen-
sor 1/1 Signal circuit at the 1/1 O2 Sensor harness connector.
Does the test light illuminate brightly?
Ye s>>
Repair the short to voltage in the (K41) O2 Sensor 1/1 Sig-
nal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3

3.(K41) O2 SENSOR 1/1 SIGNAL CIRCUIT OPEN
Turn the ignition off.
Measure the resistance of the (K41) O2 Sensor 1/1 Signal circuit from
the O2 Sensor harness connector to the C1 PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 4
No>>
Repair the open in the (K41) O2 Sensor 1/1 Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
4.(K41) O2 SENSOR 1/1 SIGNAL CIRCUIT SHORTED TO THE (K343) ASD RELAY OUTPUT CIRCUIT
Measure the resistance between the (K41) O2 Sensor 1/1 Signal circuit
and the (K343) ASD Relay Output circuit at the O2 Sensor harness con-
nector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short between the O2 Sensor Signal circuit and
the (K343) ASD Relay Output circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5

5.(K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor ground circuit from the O2
Sensor harness connector to the C1 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.(K343) ASD RELAY OUTPUT CIRCUIT OPEN
Connect the PCM harness connectors.
Ignition on, engine not running.
With the scan tool actuate the O2 Heater Test.
Using a 12-volt test light connected to ground, probe the (K343) ASD
Relay Output circuit.
Does the test light illuminate brightly?
Ye s>>
Go To 7
No>>
Repair the open in the (K343)ASD Relay Output circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)

7.(K99) O2 SENSOR 1/1 HEATER CONTROL CIRCUIT OPEN
Turn the ignition off.
Disconnect the C3 PCM harness connector.
Measure the resistance of the (K99) O2 Sensor 1/1 Heater Control cir-
cuit from the O2 Sensor harness connector to the PCM harness con-
nector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 8
No>>
Repair the open in the (K99) O2 Sensor 1/1 Heater Control
Circuit (PWM) circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
8.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)

When Monitored:
With ECT greater than 147°F, after reaching a vehicle speed of 10 mph, and the throttle remaining open (off
idle) for 2 minutes, bring the vehicle to a stop and allow the engine to idle with the transmission in DRIVE.
Set Condition:
The oxygen sensor signal voltage is switching from below 0.27 of a volt to above 0.62 of a volt and back fewer
times than required.
Possible Causes
EXHAUST LEAK
(K41) O2 1/1 SIGNAL CIRCUIT
(K900) SENSOR GROUND CIRCUIT
O2 SENSOR
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Check for contaminants that may have damaged the O2 Sensor: contaminated fuel, unapproved sil-
icone, oil and coolant.
Ignition on, engine not running.
NOTE: After the repairs have been made, verify proper O2 Sensor operation.If all the O2 Sensor voltage
readings have not returned to normal, follow the diagnostic procedure forthe remaining O2 Sensors.
With a scan tool, read DTCs.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Symptom. (Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING)
2.EXHAUST LEAK
Start the engine.
Inspect the exhaust system for leaks between the engine and the O2 Sensors.
Are there any exhaust leaks?
Ye s>>
Repair or replace the leaking exhaust parts as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
3.(K41) O2 1/1 SIGNAL CIRCUIT VOLTAGE DROP
Turn the ignition off.
While backprobing, measure the voltage of the (K41) O2 Sensor 1/1 Signal circuit between the 1/1 O2 Sensor har-
ness connector and PCM harness connector.
NOTE: Make sure the voltmeter leads meet the terminals in the connector andthat there is good terminal to
wire connection and are connected for positive polarity.
Start the engine.

Allow the engine to idle.
Is the voltage below 0.10 of a volt?
Ye s>>
Go To 4
No>>
Repair the excessive resistance in the (K41) O2 Sensor 1/1 Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
4.(K900) SENSOR GROUND CIRCUIT VOLTAGE DROP
Turn the ignition off.
While backprobing, measure the voltage of the (K900) Sensor ground circuit between the 1/1 O2 Sensor harness
connector and PCM harness connector.
NOTE: Make sure the voltmeter leads meet the terminals in the connector andthat there is good terminal to
wire connection.
NOTE: Make sure the voltmeter leads are connected for positive polarity
Start the engine.
Allow the engine to idle.
Is the voltage below 0.10 of a volt?
Ye s>>
Go To 5
No>>
Repair the excessive resistance in the (K900) Sensor ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
NOTE: Turn the ignition off before continuing.
5.O2 SENSOR
If there are no possible causes remaining, view repair.
Repair
Replace the O2 Sensor
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)