• | 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 provide an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
---|---|---|---|
IAH Temperature Signal | -- | P154D | P154D |
IAH Command 2 | P154B | P154B | P154B |
IAH Voltage Signal | P154B | P154B | P154B |
IAH Command 1 | P154B | P154B | P0640 |
IAH Current Signal | P154C | P154C | P154C |
IAH Feedback Signal | P154A | P154A | P154A |
IAH Battery Positive Voltage | -- | P154B | -- |
The intake air heater (IAH) is located in the air inlet tube and is used to warm the incoming air to aid in starting the engine and for proper cylinder combustion. The glow plug control module (GPCM) will command the IAH ON when the engine coolant temperature is below 40°C (104°F). The IAH is connected to the GPCM by the following circuits:
• | The IAH temperature signal circuit |
• | The IAH command 1 circuit |
• | The IAH command 2 circuit |
• | The IAH voltage signal circuit |
• | The IAH current signal circuit |
• | The IAH feedback signal circuit |
⇒ | If there is a fault on any of these circuits, a DTC will set. |
Power to the IAH is supplied by the battery positive voltage circuit. An open/high resistance or a short to ground on this circuit will also set DTC P154B.
• | The IAH is commanded ON. |
• | The GPCM battery voltage is between 9.5-15 volts. |
• | DTC P154B runs continuously when the above condition is met. |
Voltage at the IAH voltage signal is 16 volts or more.
DTC P154B is a Type B DTC.
DTC P154B is a Type B DTC.
A loose connection on the battery positive voltage circuit terminal 1 X2 of the IAH, or at the 175A Mega Fuse terminal 1 X4 of the Underhood Fuse Holder, may cause this DTC to set.
Intake Air Heater System Description
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
⇒ | If the test lamp does not illuminate, test the circuit for an open/high resistance or a short to ground and repair as necessary. |
• | The IAH command 1 circuit between terminal 31 X2 of the GPCM and terminal 2 X1 of the IAH |
• | The IAH command 2 circuit between terminal 26 X2 of the GPCM and terminal 3 X1 of the IAH |
• | The IAH voltage signal circuit between terminal 30 X2 of the GPCM and terminal 5 X1 of the IAH |
⇒ | If a condition was found on any of the circuits repair as necessary. |
⇒ | If the IA Heater Undervoltage parameter displays Fault, replace the intake air heater. |
⇒ | If the IA Heater Undervoltage parameter does not display Fault, replace the GPCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for GPCM replacement, setup, and programming |