P16A8

DTC P16A8

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 provides an overview of each diagnostic category.

DTC Descriptor

DTC P16A8
- Glow Plug Control Module Temperature - Intake Air Heater Temperature Correlation

Circuit/System Description

The glow plug control module has the ability to perform internal diagnostics for voltage and output state of the glow plugs. If the difference between the internal temperature of the glow plug control module and the internal temperature of the intake air heater module is greater than 20°C (68°F), this DTC will set. The glow plug control module will send a message to the engine control module (ECM) to set this DTC.

Conditions for Running the DTC

* The ignition is ON.

* Engine off timer is greater than or equal to 28,800 seconds.

* Intake air temperature is greater than -7°C (19°F).

* Intake air heater pulse width modulation equals 100 percent.

* DTC P154D is not set.

Conditions for Setting the DTC

The difference between the internal temperature of the glow plug control module and the internal temperature of the intake air heater module is greater than 20°C (68°F).

Action Taken When the DTC Sets

DTC P16A8 is a Type B DTC.

Conditions for Clearing the DTC

DTC P16A8 is a Type B DTC.

Diagnostic Aids

Ensure the glow plug control module is clear of any aftermarket devices.

Reference Information

Schematic Reference

Engine Controls Schematics (LGH or LML) [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)

Description and Operation

Glow Plug System Description Glow Plug 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

1. If you cannot duplicate the conditions, refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections.

2. 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: Verify there are no aftermarket air flow restrictions near the glow plug control module.

Verify there are no other DTC's present.

If other DTC's are present, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

If there are no other DTC's and DTC P16A8 is present, replace the K34 glow plug control module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

Control Module References Control Module References for glow plug control module replacement, setup, and programming