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Electronic Control System Gas Plus Engines – FAULT CODE 143 – L Gas Plus

Engine Oil Pressure Low – Warning

Overview

Engine Oil Pressure Low – Warning

CODE REASON EFFECT
Fault Code: 143
PID: P100
SPN: 100
FMI: 1/18
LAMP: Yellow
SRT: 

Engine Oil Pressure Low – Warning. Engine oil pressure signal indicates engine oil pressure below the engine protection warning limit.

Progressive power derate increasing in severity from time of alert. If engine protection shutdown is enabled, the engine will shutdown after 30 seconds of the red lamp flashing.

Engine Oil Pressure Sensor Circuit
SMALL | MEDIUM | LARGE

Circuit Description

The oil pressure sensor is used by the electronic control module (ECM) to monitor the lubricating oil pressure. The ECM monitors the voltage on the signal pin and converts this to a pressure value. The oil pressure value is used by the ECM for the engine protection system.

Component Location

The oil pressure sensor is located on the engine block, on the fuel system side.

Shop Talk

Verify with the driver the engine speed at which the fault occurs. If the engine is being operated at too low of a speed, the oil pressure can drop below the engine protection limits.

Possible causes:

  • Low oil level
  • Low operation speeds
  • Oil dilution
  • Oil filter needs to be changed.

The L Gas Plus uses only a pressure sensor.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Check the engine oil pressure sensor accuracy.  
  STEP 1A. Check the sensor accuracy. Sensor reading is correct?
STEP 2. Check engine oil pressure.  
  STEP 2A. Check engine oil pressure with a mechanical gauge. Is oil pressure greater than 48 kPa [7 psi]?
STEP 3. Clear the fault codes.  
  STEP 3A. Disable the fault code. Fault Code 143 inactive?
  STEP 3B. Clear the inactive fault codes. All fault codes cleared?

Guided Step 1 – Check the engine oil pressure sensor accuracy.

Guided Step 1A – Check the sensor accuracy.

Conditions

  • Connect a mechanical oil pressure gauge to the engine.
  • Connect INSITE™ electronic service tool to the vehicle data link.

Action

  • Start the engine and compare the oil pressure reading on the service tool monitor screen to the reading on the mechanical oil pressure gauge. The pressure sensor displays in absolute, add atmospheric pressure to gauge reading.

Sensor reading is correct?
YES NO
No Repair

Replace the sensor if electronic service tool reading differs from mechanical gauge reading. Refer to Procedure 019-066.

Guided Step 2 – Check engine oil pressure.

Guided Step 2A – Check the engine oil pressure with a mechanical gauge.

Conditions

  • Turn keyswitch on
  • Connect a mechanical oil pressure gauge
  • Connect INSITE™ electronic service tool
  • Engine running at idle speed.

Action

  • Refer to Procedure 007-052 in the Troubleshooting and Repair Manual C Gas, C Gas Plus, and L Gas Plus Engines, Bulletin 3666206.

Is oil pressure greater than 48 kPa [7 psi]?
YES NO
No Repair No Repair

Refer to the Lubricating Oil Pressure Low troubleshooting symptom tree.

Guided Step 3 – Clear the fault codes.

Guided Step 3A – Disable the fault code.

Conditions

  • Connect all components
  • Turn keyswitch ON.

Action

  • Start the engine and let it idle for one minute.
  • Verify that Fault Code 143 is inactive.

Note: If the fault was at a particular speed, run the engine at that speed to verify the problem is corrected.

Fault Code 143 inactive?
YES NO
No Repair

Repeat the troubleshooting steps. If fault code remains active, go to the Low Oil Pressure symptom tree in Section TS.

Guided Step 3B – Clear the inactive fault codes.

Conditions

  • Connect all components.
  • Turn keyswitch ON.

Action

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

All fault codes cleared?
YES NO
No Repair

Troubleshoot any remaining active fault codes.
Repair complete.
Appropriate troubleshooting charts
Last Modified:  06-Aug-2004
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Published by Jack

Hello, I'm Jack, a diesel engine fan and a blogger. I write about how to fix and improve diesel engines, from cars to trucks to generators. I also review the newest models and innovations in the diesel market. If you are interested in learning more about diesel engines, check out my blog and leave your feedback.