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FAULT CODE 122

Intake Manifold Pressure Sensor Circuit

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Overview

CODE REASON EFFECT
Fault Code: 122
PID: P102
SPN: 102
FMI: 3
LAMP: Yellow
SRT: 00-093		 High voltage detected at intake manifold pressure sensor signal pin 26 of the sensor harness connector. Possible engine derate.

Intake Manifold Pressure Sensor Circuit

Circuit Description

The intake manifold pressure sensor monitors intake manifold pressure and passes information to the electronic control module (ECM) through the sensor harness. If the intake manifold pressure becomes too high, it will cause a possible derate condition.

Component Location

The intake manifold pressure sensor is located on the intake air manifold.

Shop Talk

  • Determine if engine is being overfueled.
  • Confirm that the correct intake manifold pressure sensor part number is being used.
  • Confirm that the correct turbocharger is being used.
  • If it is suspected that cold intake air is the cause of the high intake manifold pressure, test the engine with warm intake air.
  • Inspect the intake manifold pressure sensor circuit for signs of tampering. Remove any extra wires from the circuit.

Cautions and Warnings

 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test leads when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead
Part Number 3822917 – female Deutsch/AMP/Metri-Pack test lead
Part Number 3824776 – breakout cable.
 CAUTION 

 

To reduce the possibility of damaging a new ECM, all other active fault codes must be investigated prior to replacing the ECM.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3824776 – breakout cable.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822917 – female Deutsch/AMP/Metri-Pack test lead.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822917 – female Deutsch/AMP/Metri-Pack test lead.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use this test lead when taking a measurement:
Part Number 3822917 – female Deutsch/AMP/Metri-Pack test lead.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Check the intake manifold pressure sensor.
STEP 1A. Check the intake manifold pressure sensor. No damaged pins
STEP 1B. Read the fault codes. Fault Code 122 active
STEP 1C. Check the intake manifold pressure sensor supply voltage. 4.75 to 5.25 VDC
STEP 1C-1. Measure the voltage to the sensor.
STEP 1C-2. Measure the voltage from the ECM.
STEP 1D. Check the intake manifold pressure sensor signal voltage. 0.42 to 0.58 VDC
STEP 1D-1. Check for a short circuit pin to pin.
STEP 1D-2. Check for continuity in sensor harness.
STEP 1D-3. Check ECM response.
STEP 1D-4. Check signal pin to return resistance.
STEP 2. Check the sensor harness and the ECM.
STEP 2A. Inspect the sensor harness and the ECM connector pins. No damaged pins
STEP 2B. Read the fault codes. Fault Code 122 active
STEP 2C. Check for a short circuit from pin to pin. More than 100k ohms
STEP 2D. Check for continuity in sensor harness. Less than 10 ohms
STEP 3. Check for ECM response.
STEP 3A. Check for the appropriate ECM response. Fault Code 122 inactive, Fault Code 123 active
STEP 3B. Check ECM signal to ground resistance. Less than 100k ohms
STEP 4. Clear the fault codes.
STEP 4A. Disable the fault code. Fault Code 122 inactive
STEP 4B. Clear the inactive fault codes. All fault codes cleared

Guided Step 1 – Check the intake manifold pressure sensor.

Guided Step 1A – Inspect the intake manifold pressure sensor and sensor harness connector pins.

Conditions

  • Turn keyswitch OFF.
  • Disconnect the sensor harness from the intake manifold pressure sensor.
  • Flush and clean the connector pins using electronic contact cleaner, Part Number 3824510.

Action

  • Bent or broken pins
  • Pushed back or expanded pins
  • Corroded pins
  • Moisture in or on the connector
  • Missing or damaged seals
  • Dirt or debris in or on the connector pins.
OK NOT OK
No damaged pins Repair the damaged pins.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Replace the intake manifold pressure sensor. Refer to Procedure 019-061.
  • Repair the sensor harness. Refer to Procedure 019-201 or 019-202.
  • Replace the sensor harness. Refer to Procedure 019-043.
  • Install the appropriate connector seal if it is damaged or missing.
    Refer to Procedure 019-201 or 019-202.

Guided Step 1B – Read the fault codes.

Conditions

  • Turn keyswitch OFF.
  • Connect all components.

Action

  • Start the engine and let it idle for one minute.
  • Read the fault codes using INSITE™ electronic service tool.
OK NOT OK
Fault Code 122 active Repair complete.

 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3824776 – breakout cable.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3824776 – breakout cable.
 CAUTION 

 

To reduce the possibility of damaging a new ECM, all other active fault codes must be investigated prior to replacing the ECM.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822917 – female Deutsch/AMP/Metri-Pack test lead.
Guided Step 1C – Check the intake manifold pressure sensor supply voltage.

Conditions

  • Disconnect all pressure and temperature sensors from the sensor harness
    (except intake manifold pressure sensor).
  • Disconnect the coolant level sensor or shorting plug from the sensor harness.
  • Turn keyswitch ON.

Action

  • Install the intake manifold pressure sensor breakout cable, Part Number 3824776, between the sensor and the sensor harness connector.
  • Measure the supply voltage from pin A to pin B of the breakout cable.
OK NOT OK
4.75 to 5.25 VDC Does not meet specifications.

 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3824776 – breakout cable.
Guided Step 1C-1 – Measure the voltage to the sensor.

Conditions

  • Disconnect all pressure and temperature sensors from their connectors on the sensor harness.
  • Disconnect the coolant level sensor or shorting plug from its connector on the sensor harness.
  • Turn keyswitch ON.

Action

  • Install the intake manifold pressure sensor breakout cable, Part Number 3824776, to the sensor harness connector. Note: Do not connect the sensor to the breakout cable.
  • Measure the supply voltage from pin A to pin B of the breakout cable.
OK NOT OK
4.75 to 5.25 VDC

  • Replace the intake manifold pressure sensor. Refer to Procedure 019-061.
 Does not meet specifications.

 CAUTION 

 

To reduce the possibility of damaging a new ECM, all other active fault codes must be investigated prior to replacing the ECM.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822917 – female Deutsch/AMP/Metri-Pack test lead.
Guided Step 1C-2 – Measure the voltage from the ECM.

Conditions

  • Disconnect the sensor harness connector from the ECM.
  • Turn keyswitch ON.

Action

  • Measure the voltage out of the ECM from pin 2 to pin 4 at the ECM sensor port.
OK NOT OK
4.75 to 5.25 VDC

  • Repair the sensor harness. Refer to Procedure 019-203.
  • Replace the sensor harness. Refer to Procedure 019-043.
 Replace the ECM. Refer to Procedure 019-031.

 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3824776 – breakout cable.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead.
 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822917 – female Deutsch/AMP/Metri-Pack test lead.
Guided Step 1D – Check the intake manifold pressure sensor signal voltage.

Conditions

  • Disconnect all sensors from their connectors on the sensor harness, except the intake manifold pressure sensor.
  • Disconnect the coolant level sensor or shorting plug from its connector on the sensor harness.
  • Turn keyswitch ON.

Action

  • Install the intake manifold pressure sensor breakout cable, Part Number 3824776, between the sensor and the sensor harness connector.
  • Measure the signal voltage from pin C to pin B of the breakout cable.
OK NOT OK
0.42 to 0.58 VDC Does not meet specifications.

 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead.
Guided Step 1D-1 – Check for a short circuit pin to pin.

Conditions

  • Turn keyswitch OFF.
  • Disconnect the sensor harness from the ECM.
  • Disconnect all sensors and the coolant level sensor or shorting plug from their connectors.

Action

  • Measure resistance from pin 26 of the sensor harness connector at the ECM to all other pins.
  • Measure resistance from pin 4 of the sensor harness connector at the ECM to all other pins.
  • Measure resistance from pin 2 of the sensor harness connector at the ECM to all other pins.
OK NOT OK
More than 100k ohms Repair or replace the sensor harness.

  • Repair the sensor harness. Refer to Procedure 019-203.
  • Replace the sensor harness. Refer to Procedure 019-043.

 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead.
Guided Step 1D-2 – Check for continuity in sensor harness.

Conditions

  • Turn keyswitch OFF.
  • Disconnect the sensor harness connector from the ECM.
  • Disconnect the intake manifold pressure sensor from the sensor harness.

Action

  • Measure the resistance from pin 2 of the sensor harness connector to pin A of the sensor connector.
  • Measure the resistance from pin 4 of the sensor harness connector to pin B of the sensor connector.
  • Measure the resistance from pin 26 of the sensor harness connector to pin C of the sensor connector.
OK NOT OK
Less than 10 ohms Correct pin-to-pin wiring or open circuit

  • Repair the sensor harness. Refer to Procedure 019-203.
  • Replace the sensor harness. Refer to Procedure 019-043.

 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead.
Guided Step 1D-3 – Check ECM response.

Conditions

  • Disconnect sensor harness connector from the ECM.
  • Turn keyswitch ON.

Action

  • Install Part Number 3822917, as a jumper wire, between ECM sensor harness port pin 4 and pin 26.
  • Read the fault codes.
OK NOT OK
Fault Code 122 inactive, Fault Code 123 active Fault Code 122 active.

  • Replace the ECM. Refer to Procedure 019-031.

 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822917 – female Deutsch/AMP/Metri-Pack test lead.
Guided Step 1D-4 – Check signal pin to return resistance.

Conditions

  • Turn keyswitch OFF.
  • Disconnect sensor harness connector from the ECM.

Action

  • Measure the resistance from pin 26 to pin 4 at the sensor port of
    the ECM, using Part Number 3822917.
OK NOT OK
Less than 100k ohms

  • Replace the intake manifold pressure sensor. Refer to Procedure 019-061.
 Greater than 100k ohms

  • Replace the ECM. Refer to Procedure 019-031.

Guided Step 2 – Check the sensor harness and the ECM.

 CAUTION 

 

To reduce the possibility of damaging a new ECM, all other active fault codes must be investigated prior to replacing the ECM.
Guided Step 2A – Inspect the sensor harness and the ECM connector pins.

Conditions

  • Turn keyswitch OFF.
  • Disconnect the sensor harness connector from the ECM.
  • Flush and clean the connector pins using electronic contact cleaner, Part Number 3824510.

Action

  • Bent or broken pins
  • Pushed back or expanded pins
  • Corroded pins
  • Moisture in or on the connector
  • Missing or damaged seals
  • Dirt or debris in or on the connector pins.
OK NOT OK
No damaged pins Repair the damaged pins.

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Repair the sensor harness. Refer to Procedure 019-203.
  • Replace the sensor harness. Refer to Procedure 019-043.
  • Replace the ECM. Refer to Procedure 019-031.
  • Replace the o-ring on the 28-pin connector if it is damaged or missing. Refer to Procedure 019-203.

Guided Step 2B – Read the fault codes.

Conditions

  • Turn keyswitch OFF.
  • Connect all components.

Action

  • Start the engine and let it idle for one minute.
  • Read the fault codes using INSITE™ electronic service tool.
OK NOT OK
Fault Code 122 active Repair complete.

 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead.
Guided Step 2C – Check for a short circuit from pin to pin.

Conditions

  • Keyswitch OFF.
  • Disconnect the sensor harness connector from the ECM.
  • Disconnect all sensors from their connectors on the sensor harness.
  • Disconnect the coolant level sensor or shorting plug from its connector on the sensor harness.

Action

  • Measure the resistance from pin 2 of the sensor harness connector to all other pins in the connector.
  • Measure the resistance from pin 4 of the sensor harness connector to all other pins in the connector.
  • Measure the resistance from pin 26 of the sensor harness connector to all other pins in the connector.
OK NOT OK
More than 100k ohms Repair or replace the sensor harness.

  • Repair the sensor harness. Refer to Procedure 019-203.
  • Replace the sensor harness. Refer to Procedure 019-043.

 CAUTION 

 

To reduce the possibility of pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822758 – male Deutsch/AMP/Metri-Pack test lead.
Guided Step 2D – Check for continuity in sensor harness.

Conditions

  • Turn keyswitch OFF.
  • Disconnect sensor harness connector from ECM.
  • Disconnect intake manifold pressure sensor from sensor harness.

Action

  • Measure resistance from pin 26 of sensor harness connector at ECM to pin C of sensor connector.
  • Measure resistance from pin 4 of sensor harness connector at ECM to pin B of sensor connector.
  • Measure resistance from pin 2 of sensor harness connector at ECM to pin A of sensor connector.
OK NOT OK
Less than 10 ohms Correct the pin-to-pin wiring or open circuit.

Guided Step 3 – Check for ECM response.

 CAUTION 

 

To reduce the possibility of damaging a new ECM, all other active fault codes must be investigated prior to replacing the ECM.
Guided Step 3A – Check for the appropriate ECM response.

Conditions

  • Disconnect the sensor harness connector from the ECM.
  • Turn keyswitch ON.

Action

  • Install Part Number 3822917, as a jumper wire, between ECM sensor harness port pin 4 and pin 26.
  • Read the fault codes using INSITE™ electronic service tool.
OK NOT OK
Fault Code 122 inactive, Fault Code 123 active Fault Code 122 active

  • Replace the ECM. Refer to Procedure 019-031.

 CAUTION 

 

To reduce the possibility of pin and harness damage, use this test lead when taking a measurement:
Part Number 3822917 – female Deutsch/AMP/Metri-Pack test lead.
Guided Step 3B – Check ECM signal to ground resistance.

Conditions

  • Turn keyswitch OFF.
  • Disconnect the sensor harness connector from the ECM.

Action

  • Measure the resistance from pin 26 to pin 4 of the ECM sensor port.
OK NOT OK
Less than 100k ohms Replace the ECM. Refer to Procedure 019-031.

Guided Step 4 – Clear the fault codes.

Guided Step 4A – Disable the fault codes.

Conditions

  • Connect all components.

Action

  • Start the engine and let it idle for one minute.
  • Verify that Fault Code 122 inactive.
OK NOT OK
Fault Code 122 inactive Return to troubleshooting steps or contact your nearest Cummins Authorized Repair Location if all steps have been completed and checked again.

Guided Step 4B – Clear the inactive fault codes.

Conditions

  • Connect all components.

Action

  • Erase the inactive fault codes using INSITE™ electronic service tool .
OK NOT OK
All fault codes cleared Troubleshoot any remaining active fault codes.
Repair complete
Appropriate troubleshooting charts
Last Modified:  08-Sep-2004
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