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Electronic Control System Gas Plus Engines – FAULT CODE 154

Intake Manifold Temperature Sensor Circuit – Shorted Low

Overview

CODE REASON EFFECT
Fault Code: 154
PID: P105
SPN: 105
FMI: 4
LAMP: Amber
SRT: 

Intake Manifold Temperature Sensor Circuit – Shorted Low.

Possible reduced performance. Fan will stay ON if controlled by ECM. No engine protection for intake manifold air temperature.

Intake Manifold Temperature Sensor Circuit
SMALL | MEDIUM | LARGE

Circuit Description

The electronic control module (ECM) uses the intake manifold pressure/temperature sensor input to determine the temperature of the air mixture entering the engine.

Component Location

The intake manifold pressure/temperature sensor is located in the intake manifold housing (combination sensor with pressure).

Shop Talk

All temperature sensors:

  • The resistance of the sensor varies with temperature. The reading you observe should 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 test lead.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Check the fault codes.  
  STEP 1A. Check for an inactive fault code. Fault Code 154 active?
STEP 2. Check the intake manifold air temperature sensor and circuit.  
  STEP 2A. Inspect the intake manifold air temperature sensor and connector pins. Dirty or damaged pins?
  STEP 2B. Check the circuit response. Fault Code 153 active and Fault Code 154 inactive?
  STEP 2C. Check the fault codes and verify sensor condition. Fault Code 154 active?
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 a pin to pin short circuit in the engine harness. Greater than 100k ohms?
  STEP 3C. Check for a pin short circuit to ground. Greater than 100k ohms?
  STEP 3D. Check for an inactive fault code. Fault Code 154 inactive?
STEP 4. Clear the fault codes.  
  STEP 4A. Disable the fault code. Fault Code 154 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 code.

Conditions

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

Action

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

Fault Code 154 inactive?
YES NO
No Repair No Repair

Guided Step 2 – Check the intake manifold air temperature sensor and circuit.

Guided Step 2A – Inspect the intake manifold air temperature sensor and connector pins.

Conditions

  • Turn keyswitch OFF
  • Disconnect the intake manifold air temperature sensor from the engine harness.

Action

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

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 019-204
  • Replace the engine harness. Refer to Procedure 019-043.
 No Repair

Guided Step 2B – Check the circuit response

Conditions

  • Turn keyswitch OFF
  • Disconnect the intake manifold air temperature sensor from the engine harness
  • Turn keyswitch ON
  • Connect INSITE™ electronic service tool.

Action

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

Fault Code 153 active and Fault Code 154 inactive?
YES NO
No Repair No Repair

Guided Step 2C – Check the fault codes and verify sensor condition.

Conditions

  • Turn keyswitch OFF
  • Disconnect the intake manifold air temperature sensor from the engine harness
  • Turn keyswitch ON
  • Connect INSITE™ electronic service tool.

Action

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

Fault Code 154 active?
YES NO

A defective sensor has been detected.

Replace the intake manifold air temperature sensor. Refer to Procedure 019-354.

 No Repair

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 engine harness connector 1 from the ECM.

Action

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

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.

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 a pin to pin short circuit in the engine harness.

Conditions

  • Turn keyswitch OFF
  • Disconnect the engine harness connector 1 and connector 2 from the ECM
  • Disconnect the intake manifold air temperature sensor from the engine harness.

Action

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

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

For general resistance measurement techniques refer to the Resistance 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 engine harness, whichever has the damaged pins.

  • Repair the engine harness. Refer to Procedure 019-204
  • Replace the engine harness. Refer to Procedure 019-043.

Guided Step 3C – Check for a pin short circuit to ground.

Conditions

  • Turn keyswitch OFF
  • Disconnect engine harness connector 1 from the ECM
  • Disconnect the intake manifold pressure/temperature sensor from the engine harness.

Action

  • Measure the resistance between the intake manifold air temperature SIGNAL pin in engine harness ECM connector 1 to ground.
SMALL | MEDIUM | LARGE

Greater than 100k ohms?
YES NO
No Repair

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

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

  • Repair the engine harness. Refer to Procedure 019-204
  • Replace the engine harness. Refer to Procedure 019-043.

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

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 154 inactive?
YES NO
No Repair

Replace the ECM. Call for pre-authorization. Refer to Procedure 019-031.

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 154 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 charts
Last Modified:  28-Sep-2004
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