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Electronic Control System Gas Plus Engines – FAULT CODE 212

Oil Temperature Sensor Circuit – Shorted High

Overview

CODE REASON EFFECT
Fault Code: 212
PID: P175
SPN: 175
FMI: 3
LAMP: Amber
SRT: 

Oil Temperature Sensor Circuit – Shorted High. High signal voltage detected on the oil temperature signal pin at the ECM.

None on performance. No engine protection for oil temperature.

Oil Temperature Sensor Circuit
SMALL | MEDIUM | LARGE

Circuit Description

The electronic control module (ECM) uses this combination pressure/temperature sensor for engine protection purposes.

Component Location

The engine oil pressure/temperature sensor is located in the block on the fuel system side of the engine.

Shop Talk

All temperature sensors:

  • The resistance of the sensor varies with temperature. The reading observed must compare to the following table if the sensor is functioning properly.
Temperature (°C) Temperature [°F] Resistance (ohms)
0 32 30k to 36k
25 77 9k to 11k
50 122 3k to 4k
75 167 1350 to 1500
100 212 600 to 675

Cautions and Warnings

 CAUTION 

To reduce the possibility of damaging a new ECM, all other active fault codes must be investigated prior to replacing the ECM.
 CAUTION 

To reduce the possibility of pin and harness damage, use the following test leads when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead
Part Number 3822917 – female Deutsch/AMP/Metri-Pack lead.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Check the fault codes.  
  STEP 1A. Check for an inactive fault code. Fault Code 212 inactive?
STEP 2. Check the oil temperature sensor and circuit.  
  STEP 2A. Inspect the engine oil temperature sensor and connector pins. Dirty or damaged pins?
  STEP 2B. Check the sensor resistance. 175 ohms to 274k ohms?
STEP 3. Check the ECM and engine harness.  
  STEP 3A. Inspect the ECM and engine harness connector pins. Dirty or damaged pins?
  STEP 3B. Check for an open circuit in the engine harness. Less than 10 ohms?
  STEP Checkforanopencircuitintheengineharness..
  STEP 3C. Check for a pin to pin short circuit in the engine harness. Greater than 100k ohms?
  STEP 3D. Check for an inactive fault code. Fault Code 212 inactive?
STEP 4. Clear the fault codes.  
  STEP 4A. Disable the fault code. Fault Code 212 inactive?
  STEP 4B. Clear the inactive fault codes. All fault codes cleared?

Guided Step 1 – Check the fault codes.

Guided Step 1A – Check for an inactive fault codes.

Conditions

  • Turn keyswitch ON
  • Connect INSITE™ electronic service tool.

Action

Use INSITE™ electronic service tool to read the fault codes.

Fault Code 212 inactive?
YES NO
No Repair No Repair

Guided Step 2 – Check the oil temperature sensor and circuit.

Guided Step 2A – Inspect the oil pressure/temperature sensor and connector pins.

Conditions

  • Turn keyswitch OFF
  • Disconnect the oil temperature sensor from the engine harness.

Action

  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Wire insulation damaged
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Connector shell broken
  • Dirt or debris in or on the connector pins.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general inspection techniques, refer to Component Connector and Pin Inspection, Procedure 019-361.

Dirty or damaged pins?
YES NO

A defective connection has been detected in the sensor or harness connector.

Repair the damaged pins. Repair or replace the engine harness, whichever has the damaged pins.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Install the appropriate connector seal if it is damaged or missing.
  • Repair the engine harness. Refer to Procedure 019-202.
  • Replace the engine harness. Refer to Procedure 019-043.
No Repair

Guided Step 2B – Check the sensor resistance.

Conditions

  • Turn keyswitch OFF
  • Disconnect the engine oil temperature sensor from the engine harness.

Action

  • Measure the resistance between the SIGNAL pin and RETURN pin at the oil temperature sensor connector.

Refer to the circuit diagram or wiring diagram for connector pin identification.

For general resistance measurement techniques, refer to Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360.

175 to 274k ohms?
YES NO

Refer to the table in shop talk for specifications.

Replace the engine oil temperature sensor. Refer to Procedure 019-155.

Guided Step 3 – Check the ECM and engine harness.

Guided Step 3A – Inspect the ECM and engine harness connector pins.

Conditions

  • Turn keyswitch OFF
  • Disconnect the engine harness from the ECM.

Action

  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Wire insulation damaged
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Connector shell broken
  • Dirt or debris in or on the connector pins.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general inspection techniques, refer to Component Connector and Pin Inspection, Procedure 019-361.

Dirty or damaged pins?
YES NO

A defective connection has been detected in the ECM connector or engine harness connector.

Repair the damaged pins. Repair or replace the engine harness, whichever has the damaged pins.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Install the appropriate connector seal if it is damaged or missing.
  • Repair the engine harness. Refer to Procedure 019-204.
  • Replace the engine harness. Refer to Procedure 019-043.
No Repair

Guided Step 3B – Check for an open circuit in the engine harness.

Conditions

  • Turn keyswitch OFF
  • Disconnect engine harness from the ECM.
  • Disconnect the oil temperature sensor from the engine harness.

Action

  • Measure the resistance between the oil temperature RETURN pin and the ECM connector 1 RETURN pin.

Refer to the circuit diagram or wiring diagram for connector pin identification.

For general resistance measurement techniques, refer to Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360.

Less than 10 ohms?
YES NO
No Repair

An open circuit has been detected in the engine harness.

Repair or replace the harness.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Install the appropriate connector seal if it is damaged or missing.
  • Repair the engine harness. Refer to Procedure 019-202.
  • Replace the engine harness. Refer to Procedure 019-043.

Guided Step 3B-1 – Check for an open circuit in the engine harness.

Conditions

  • Turn keyswitch OFF
  • Disconnect engine harness from the ECM.
  • Disconnect the oil temperature sensor from the engine harness.

Action

  • Measure the resistance between the engine oil temperature sensor SIGNAL pin and the ECM connector 1 SIGNAL pin.

Refer to the circuit diagram or wiring diagram for connector pin identification.

For general resistance measurement techniques, refer to Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360.

Less than 10 ohms?
YES NO
No Repair

An open signal circuit has been detected in the engine harness.

Repair or replace the harness.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Install the appropriate connector seal if it is damaged or missing.
  • Repair the engine harness. Refer to Procedure 019-202.
  • Replace the engine harness. Refer to Procedure 019-043.

Guided Step 3C – Check for a pin to pin short circuit in the engine harness.

Conditions

  • Turn keyswitch OFF
  • Disconnect engine harness from the ECM.
  • Disconnect the oil temperature sensor from the engine harness.

Action

  • Measure the resistance between the oil temperature SIGNAL pin in engine harness and all other pins in the ECM connector 1.
  • Measure the resistance between the oil temperature SIGNAL pin in engine harness and all other pins in the ECM connector 2.

Refer to the circuit diagram or wiring diagram for connector pin identification.

For general resistance measurement techniques, refer to Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360.

Greater than 100k ohms?
YES NO
No Repair

A pin to pin short circuit on the SIGNAL line has been detected in the engine harness.

Repair or replace the harness.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Install the appropriate connector seal if it is damaged or missing.
  • Repair the engine harness. Refer to Procedure 019-202.
  • Replace the engine harness. Refer to Procedure 019-043.

Guided Step 3D – Check for an inactive fault codes.

Conditions

  • Connect all components
  • Turn keyswitch ON
  • Connect INSITE™ electronic service tool.

Action

Use INSITE™ electronic service tool to read the fault codes.

Fault Code 212 inactive?
YES NO
No Repair No Repair

Guided Step 4 – Clear the fault codes.

Guided Step 4A – Disable the fault code.

Conditions

  • Connect all components
  • Turn keyswitch ON
  • Connect INSITE™ electronic service tool.

Action

  • Start the engine and let it idle for one minute.
  • Use INSITE™ electronic service tool to verify that the fault code is inactive.

Fault Code 212 inactive?
YES NO
No Repair No Repair

Guided Step 4B – Clear the inactive fault codes.

Conditions

  • Connect all components
  • Turn keyswitch ON
  • Connect INSITE™ electronic service tool.

Action

  • Use INSITE™ electronic service tool to erase the inactive fault codes

All fault codes cleared?
YES NO
No Repair No Repair
Repair complete
Appropriate troubleshooting steps
Last Modified:  03-Sep-2004
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