P154D
DTC P154D
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provide an overview of each diagnostic category.
DTC Descriptor
DTC P154D
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Intake Air (IA) Heater Temperature Signal Circuit.
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The intake air heater is located in the air inlet tube and is used to warm the incoming air to aid in cylinder combustion during cold weather operation. The engine control module (ECM) sends commands to the glow plug control module to enable or disable the intake air heater when certain conditions met. The glow plug control module monitors the voltage and feedback circuits of the intake air heater to verify proper operation. If the Intake Air Heater Temperature Signal circuit is opened, shorted to voltage, or shorted to ground DTC P154D may set.
Conditions for Running the DTC
* The intake air heater is commanded ON.
* The intake air heater battery voltage is between 6.9-16 V.
* DTC P154D runs continuously when the above conditions are met.
Conditions for Setting the DTC
* The glow plug control module detected an open, short to ground or short to battery on the intake air heater temperature signal circuit for greater than 650 ms.
* The intake air heater temperature sensor value is less than -20°C (-4°F) and the intake air temperature sensor is greater than 20°C (68°F).
Action Taken When the DTC Sets
DTC P154D is a Type B DTC.
Conditions for Clearing the DTC
DTC P154D is a Type B DTC.
Diagnostic Aids
A poor intake air heater ground may cause this DTC to set.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Description and Operation
Intake Air Heater System Description Intake Air Heater System Description
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
Observe the following with a scan tool.
1. The IA Htr. Temp. Sig. Ckt. Status parameter should display OK.
2. The intake air heater can be commanded ON with a scan tool.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Note:
You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
1. Ignition OFF, disconnect the X1 harness connector of the E24 intake air heater.
2. Ignition ON, measure for 4-5 V between the temperature signal circuit terminal 1 of the intake air heater X1 connector and ground.
• If greater than the specified range, test the temperature signal circuit for a short to voltage. If the circuit tests normal, replace the K34 glow plug control module.
• If less than the specified range, test the temperature signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the K34 glow plug control module.
• If within the specified range, replace the E24 intake air heater.
Component Testing
Disconnect the intake air heater and measure between the temperature signal circuit terminal 1 on the intake air heater and ground for 15,000-18,000 ohms with a DMM.
If the DMM does not measure between 15,000-18,000 ohms, replace the E24 intake air heater.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Intake Air Heater Replacement Service and Repair
* Control Module References Control Module References for glow plug control module replacement, programming, and setup.