CM850 Electronic Control System – FAULT CODE 295

Barometric Pressure — Data Erratic, Intermittent, or Incorrect


Overview

CODE REASON EFFECT
Fault Code: 295
PID: P108
SPN: 108
FMI: 2
LAMP: Amber
SRT: 

Barometric Pressure —Data Erratic, Intermittent, or Incorrect. The barometric air pressure sensor is reading an erratic value at initial key-on.

Engine power derate

Circuit:
SMALL | MEDIUM | LARGE

Circuit Description

The barometric pressure sensor is used by the electronic control module (ECM) to monitor the barometric pressure. This value is one of many inputs used by the ECM to determine the correct air/fuel ratio for proper engine operation.

Component Location

The barometric pressure sensor is mounted on the main branch of the engine harness near the ECM. 100-002 (Engine Diagrams) in Section E for a detailed component location view.

Shop Talk

The engine barometric pressure reading is compared to the other pressure sensor values at initial key-on. If the value of engine barometric pressure does not match the readings from pressure sensors within a pre-defined tolerance, this fault code is logged. To make the diagnostic run, turn the keyswitch on for 15 seconds before cranking the engine.

Possible causes of this fault code include:

  • Stuck in-range barometric pressure sensor reading
  • High resistance in the barometric pressure sensor signal or return lines
  • Stuck in-range intake manifold pressure sensor.

On-Board Diagnostics (OBD) Information (Euro 4 Certified Engines):

  • The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
  • The ECM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. The MIL lamp and fault code can also be cleared using the INSITE™ service tool.
  • The fault code will be cleared from memory after 40 consecutive drive cycles where the diagnostic runs and passes.

On-Board Diagnostics (OBD) Information (Euro 4 Stage 1+ Certified Engines):

  • The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
  • An engine torque derate will be activated after 50 hours of engine operation with the fault code active.
  • The ECM turns OFF the malfunction indicator lamp (MIL) after 1 ignition cycles that the diagnostic runs and does not fail. The MIL lamp cannot be cleared using the INSITE™ service tool.
  • The fault code will be cleared from memory after 400 days or 9600 hours of engine operation.

Refer to Troubleshooting Fault Code t05-295

Last Modified:  08-Jul-2010