SAAB WIS ONLINE

DTC P0116 (LLU)

DTC P0116 (LLU)

Diagnostic Instructions


• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• Diagnostic Procedure Instructions provides an overview of each diagnostic category.


DTC Descriptor

DTC P0116 00

Engine Coolant Temperature (ECT) Sensor Performance

Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Signal Circuit

P0117 00

P0118 00

P0118 00*

P0116 00

Low Reference

-

P0118 00

P0118 00*

P0116 00

*ECM or sensor damage may occur if the circuit is shorted to B+



Typical Scan Tool Data

ECT Sensor

Circuit Short to Ground Open Short to Voltage
Operating Conditions: Engine operating in closed loop

Parameter Normal Range: Varies with coolant temperature

Signal

150°C (302°F)

-40°C (-40°F)

-40°C (-40°F)

Low Reference

-

-40°C (-40°F)

-40°C (-40°F)



Circuit/System Description

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 V to the ECT sensor signal circuit and a ground for the low reference circuit.

The purpose of this diagnostic is to determine if the input from the ECT sensor is skewed warmer than normal. The internal clock in the ECM registers how long the engine is OFF. If the time that the engine must be OFF has been fulfilled when starting then the ECM compares the temperature difference between the actual measured ECT with a calibrated ECT model. The information for this model is derived from the previous drive cycle and includes the accumulated mass air flow (MAF), the engine run time, the ambient air temperature and the ECT at the end of the drive cycle.

If the ECM detects that the temperature difference between the measured and modeled ECT is not within an acceptable operating range of each other, then the ECM will continue to run this diagnostic to determine if a block heater was active during the engine OFF time.

Conditions for Running the DTC


• DTCs P0112 00, P0113 00, P0117 00, P0118 00, and P2610 00 are not set.

• The ignition has been off for greater than 8 h before the engine is started.

• The engine is running.

• This DTC runs once per ignition cycle when the above conditions are met.


Conditions for Setting the DTC

The ECM does not detect an ECT sensor change of greater than 10.5°C (50.9°F) within a calibrated time.

Action Taken When the DTC Sets

DTC P0116 00 is a Type B DTC.

Conditions for Clearing the DTC

DTC P0116 00 is a Type B DTC.

Diagnostic Aids


• Inspect the ECT sensor terminals for corrosion and for engine coolant leaking through the sensor. Engine coolant that is leaking through the sensor will create a high resistance short to ground. This condition results in less voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a warmer ECT.

• An intake air temperature (IAT) sensor that is biased colder at various ambient temperatures due to greater resistance than is normal will increase the range between these two sensors. Measure and record the resistance of the IAT sensor at various ambient temperatures, then compare those measurements to the Temperature vs. Resistance table. Refer to Temperature Versus Resistance .

• Test the ECT sensor at various temperature levels in order to evaluate the possibility of a biased sensor. A sensor that is biased warmer can result in a driveability condition. Refer to Temperature Versus Resistance .

• A slight to moderate resistance in the IAT sensor signal circuit or low reference circuit will increase the range between these two sensors. This condition results in a greater voltage on the IAT sensor signal circuit, which is interpreted by the ECM as a colder IAT.

• If the condition is intermittent, it can be isolated by letting the vehicle stand still for more than 8 hours with the ignition OFF. Compare the scan tool radiator fan coolant temperature sensor and ECT sensor parameters when the ignition is switched on. The Radiator Coolant Temperature Sensor and the ECT Sensor values should display within 3°C (5°F).


Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference


• Circuit Testing

• Connector Repairs

• Testing for Intermittent Conditions and Poor Connections

• Wiring Repairs


DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification


1. Ignition on, observe the DTC information with a scan tool. Verify that DTC P0112 00, P0113 00, P0117 00, or P0118 00 are not set.

2. If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

3. Ignition off, inspect the cooling system surge tank for the proper coolant level. Refer to Loss of Coolant and Cooling System Draining and Filling (LAU/A28NER) Cooling System Draining and Filling (LBS/A20DTH) Cooling System Draining and Filling (LHU/A20NFT) .

4. If the ignition has been OFF for 8 h or greater, the B75B Mass Air Flow/Intake Air Temperature Sensor (IAT 1), the B111 Turbocharger Boost Sensor (IAT 2), and the B34A Engine Coolant Temperature Sensor 1 should be within 9°C (16°F) of each other and also the ambient temperature. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2 and the ECT Sensor parameters. Compare those sensor parameters to each other and also to the ambient temperature to determine if the ECT sensor is skewed.

5.
Note

Depending on ambient temperature, it may take up to 4 min for the temperature to equalize.


Engine running, observe the ECT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current ambient temperature and the vehicle operating conditions.

6. Drive the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you have noted from the freeze frame/failure records data.


Circuit/System Testing


1. Ignition OFF, disconnect the harness connector at the B34A Engine Coolant Temperature Sensor 1.

2. Inspect the B34A Engine Coolant Temperature Sensor 1 terminals for corrosion and for engine coolant leaking through the sensor.

3. Ignition OFF for 1 min, test for less than 5 Ω between the low reference circuit terminal 2 and ground.

4. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

5. Ignition ON, verify the scan tool ECT Sensor parameter is colder than -39°C (-38°F).

6. If greater than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

7. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool ECT Sensor parameter is greater than 149°C (300°F).

8. If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

9. If all circuits test normal, test or replace the B34A Engine Coolant Temperature Sensor 1.


Component Testing


Static Test

1. Ignition off, disconnect the harness connector at the B34A Engine Coolant Temperature Sensor 1.

2.
Note

A thermometer can be used to test the sensor off vehicle.


Test the B34A Engine Coolant Temperature Sensor 1 by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance table and verify that the resistance is within 5% of the specification.

3. If not within the specified range, replace the B34A Engine Coolant Temperature Sensor 1.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• Engine Coolant Temperature Sensor Replacement (Thermostat Housing) Engine Coolant Temperature Sensor Replacement (Radiator)

• Control Module References for ECM replacement, setup, and programming