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Electronic Control System Gas Plus Engines – FAULT CODE 2319

Exhaust Back Pressure Low Warning – Under Pressure

Overview

CODE REASON EFFECT
Fault Code: 2319
PID: S34
SPN: 648
FMI: 1/18
LAMP: Amber
SRT: 

Exhaust Back Pressure Low – Warning. Low exhaust back pressure or the sensor signal line has been broken.

Possible reduced performance.

Exhaust Back Pressure Sensor Circuit
SMALL | MEDIUM | LARGE

Circuit Description

The electronic control module (ECM) uses this sensor’s input to determine the pressure of the exhaust gas, which affects the fueling of the engine.

Component Location

The exhaust back pressure sensor is located above the rocker housing and attached to the closed-crankcase ventilation filter bracket.

Shop Talk

The arrangement of this sensor allows some condensation/sludge buildup within the tube arrangement. Before replacing the sensor, make sure this tube is free from blockage.

On the L Gas Plus, an OEM tube from the exhaust connects to a boiler box on the exhaust side of the engine. A tube then connects the box to the exhaust back pressure sensor.

A broken or disconnected exhaust back pressure tube will cause this fault to be active.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Check the exhaust back pressure.  
  STEP 1A. Check the exhaust back pressure with a mechanical gauge. Pressure between 61 to 127 mm Hg [2.4 to 5.0 in Hg]?
STEP 2. Verify the sensor accuracy.  
  STEP 2A. Compare the INSITE™ electronic service tool exhaust back pressure measurement with the mechanical gauge measurement. Is INSITE™ electronic service tool measurement the same as pressure measured with gauge?
  STEP 2B. Inspect the exhaust back pressure sensor and engine harness connector pins. Dirty or damaged pins?
STEP 3. Check the exhaust back pressure tube.  
  STEP 3A. Inspect the exhaust back pressure tube for blockage. Any blockage in tube?
STEP 4. Clear the fault codes.  
  STEP 4A. Disable the fault code. Fault Code 2319 inactive?
  STEP 4B. Clear the inactive fault codes. All fault codes cleared?

Guided Step 1 – Check the exhaust back pressure.

Guided Step 1A – Check the exhaust back pressure with a mechanical gauge.

Conditions

  • Turn keyswitch ON.

Action

Note: This test must be performed under stall test conditions.

Pressure between 61 to 127 mm Hg [2.4 to 5.0 in Hg]?
YES NO
No Repair

Exhaust back pressure not to specification. Contact the OEM regarding the exhaust system (pipe, muffler, catalytic converter).

Guided Step 2 – Verify the sensor accuracy.

Guided Step 2A – Compare the INSITE™ electronic service tool exhaust back pressure measurement with the mechanical gauge measurement.

Conditions

  • Turn keyswitch ON.

Action

  • Measure the exhaust back pressure and use INSITE™ electronic service tool to verify it is the same as the pressure reading measured with a mechanical gauge.

Is INSITE™ electronic service tool measurement the same as pressure measured with gauge?
YES NO
No Repair No Repair

Guided Step 2B – Inspect the exhaust back pressure sensor and engine harness connector pins.

Conditions

  • Turn keyswitch OFF
  • Disconnect the engine harness from the exhaust back pressure sensor.

Action

  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Dirt or debris in or on the connector pins.

Dirty or damaged pins?
YES NO

Repair or replace the engine harness, or replace the sensor, whichever has the damaged pins.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Install the appropriate connector seal if it is damaged or missing.
  • Repair the engine harness. Refer to Procedure 019-202.
  • Replace the engine harness. Refer to Procedure 019-043.
  • Replace the sensor. Refer to Procedure 019-347.
 No Repair

Guided Step 3 – Check the exhaust back pressure tube.

Guided Step 3A – Inspect the exhaust back pressure tube for blockage.

Conditions

  • Turn keyswitch OFF.

Any blockages in tube?
YES NO

Tube obstructed. Clean or replace the tube.

Replace the sensor. Refer to Procedure 019-347.

Guided Step 4 – Clear the fault codes.

Guided Step 4A – 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 2319 is inactive.

Fault Code 2319 inactive?
YES NO
No Repair

Troubleshooting procedures need to be repeated from the beginning.

Guided Step 4B – 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:  17-Aug-2004
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Published by Jack

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