Page 1 of 14 FAULT CODE Turbocharger Number 1 Compressor Inlet Temperature Sensor Circuit - Voltage Below Normal or Shorted to Low Source View Related Topic Overview CODE REASON EFFECT : PID: SPN: 1172 FMI: 4/4 LAMP: Amber SRT: Turbocharger Number 1 Compressor Inlet Temperature Sensor Circuit - Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the turbocharger compressor inlet air temperature sensor circuit. Engine power derate. Turbocharger Compressor Inlet Air Temperature Sensor Circuit Circuit Description The turbocharger compressor inlet air temperature sensor is used by the electronic control module (ECM) to monitor the temperature of the intake air temperature coming into the turbocharger. The ECM monitors the voltage on the signal pin and converts this to a temperature value. This temperature is one of many inputs used by the ECM to control engine operation and emissions. Component Location The turbocharger compressor inlet air temperature sensor is located in the compressor casing of the turbocharger. Refer to Procedure 100-002 for a detailed component location view. Shop Talk An extension harness between the main engine harness and the turbocharger compressor inlet temperature sensor may be used depending on the turbocharger arrangement.
Page 2 of 14 Possible causes of this fault code: Signal circuit shorted to ground in the harness Signal circuit shorted to return or ground in the sensor Failed sensor. The resistance of the sensor varies with temperature. The sensor resistance should conform to the values in the table shown below. Temperature ( C) Temperature ( F) Resistance (ohms) -10 14 49k to 62k 0 32 29k to 36k 20 68 11k to 14k 40 104 4.9k to 5.8k 70 158 1.6k to 1.9k Cautions and Warnings CAUTION To reduce the possibility of damaging a new ECM, all other active fault codes must be investigated prior to replacing the ECM. Troubleshooting Steps 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. STEPS SPECIFICATIONS STEP 1. Check the fault codes. STEP 2. STEP 1A. Check for an inactive fault code. Check the turbocharger compressor inlet air temperature sensor and circuit. STEP 2A. Inspect the turbocharger compressor inlet air temperature sensor and connector pins. Dirty or damaged pins?
Page 3 of 14 STEP 3. STEP 2B. Check the circuit response. STEP 2C. Check the fault codes and verify sensor condition. Check the ECM and engine harness. STEP 3A. Inspect the ECM and engine harness connector pins. STEP 3B. Check the ECM response. STEP 3C. Check for a pin-to-pin short circuit in the engine harness. STEP 3D. Check for a pin short circuit to ground. STEP 3E. Check for an inactive fault code. STEP 4. Clear the fault codes. STEP 4A. Disable the fault code. STEP 4B. Clear the inactive fault codes. 691 active and is active? Dirty or damaged pins? 691 active and Greater than 100k ohms? Greater than 100k ohms? is All fault codes cleared? Guided Step 1 - Check the fault codes. Guided Step 1A - Check for an inactive fault code. Turn keyswitch ON. Connect INSITE electronic service tool.
Page 4 of 14 check for an inactive fault code. Use INSITE electronic service tool to read the fault codes. Inactive or Intermittent Procedure 019-362 2A Guided Step 2 - Check the turbocharger compressor inlet air temperature sensor and circuit. Guided Step 2A - Inspect the turbocharger compressor inlet air temperature sensor and connector pins. Turn keyswitch OFF. Disconnect the turbocharger compressor inlet air temperature sensor from the engine harness. inspect the engine harness and sensor connector pins for the following: Loose connector Corroded pins Bent or broken pins
Page 5 of 14 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 Wire insulation damaged Connector shell broken Damaged locking tab connector. For general inspection techniques, refer to Component Connector and Pin Inspection, Procedure 019-361. Dirty or damaged pins? A defective connection has been detected in the sensor or harness connector. Dirty or damaged pins? Clean the connector and pins. Repair the damaged harness, connector, or pins if possible. Refer to Procedure 019-043. 4A 2B Guided Step 2B - Check the circuit response. Turn keyswitch OFF. Disconnect the turbocharger compressor inlet air temperature
Page 6 of 14 sensor from the engine harness. Turn keyswitch ON. Connect INSITE electronic service tool. check for the appropriate ecm response after 30 seconds. Use INSITE electronic service tool to read the fault codes. 691 active and 691 active and 2C 3A Guided Step 2C - Check the fault codes and verify sensor condition. Turn keyswitch OFF. Connect the turbocharger compressor inlet air temperature sensor to the engine harness. Turn keyswitch ON. Connect INSITE electronic service tool. check for the appropriate circuit response after 30 seconds.
Page 7 of 14 Use INSITE electronic service tool to read the fault codes. is active? A defective sensor has been detected. Replace the turbocharger compressor inlet air temperature sensor. is active? None. The removal and installation of the connector corrected the failure. Refer to Procedure 019-395. 4A 4A Guided Step 3 - Check the ECM and engine harness. Guided Step 3A - Inspect the ECM and engine harness connector pins. Turn keyswitch OFF. Disconnect the engine harness from the ECM. inspect the engine harness and ecm connector pins for the following: Loose connector Corroded pins Bent or broken pins Pushed back or expanded pins Moisture in or on the connector
Page 8 of 14 Missing or damaged connector seals Dirt or debris in or on the connector pins Wire insulation damaged Connector shell broken Damaged locking tab connector. For general inspection techniques, refer to Component Connector and Pin Inspection, Procedure 019-361. Dirty or damaged pins? A defective connection has been detected in the harness connector. Dirty or damaged pins? Clean the connector and pins. Repair the damaged harness, connector, or pins if possible. Refer to Procedure 019-043. 4A 3B Guided Step 3B - Check the ECM response. Turn keyswitch OFF. Disconnect the engine harness from the ECM. Turn keyswitch ON. Connect INSITE electronic service tool.
Page 9 of 14 check for the appropriate ecm response after 30 seconds. Use INSITE electronic service tool to read the fault codes. 691 active and 691 active and Call for pre-authorization. Replace the ECM. Refer to Procedure 019-031. 3C 4A Guided Step 3C - Check for a pin-to-pin short circuit in the engine harness. Turn keyswitch OFF. Disconnect the engine harness from the ECM. Disconnect the turbocharger compressor inlet air temperature sensor from the engine harness.
Turbocharger Number 1 Compressor Inlet Temperature Sensor Circuit - Voltage Be... Page 10 of 14 check for a pin-topin short. Measure the resistance between the turbocharger compressor inlet air temperature SIGNAL pin in the engine harness ECM connector and all other pins in the engine harness ECM connector. Refer to the wiring diagram for connector pin identification. For general resistance measurement techniques, refer to the Resistance Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360. Greater than 100k ohms? Greater than 100k ohms? A pin-to-pin short circuit on the SIGNAL line has been detected in the engine harness. Troubleshoot each harness connected in series to determine which contains the pin-to-pin shorted signal circuit. Repair or replace the engine harness.
Turbocharger Number 1 Compressor Inlet Temperature Sensor Circuit - Voltage Be... Page 11 of 14 Refer to Procedure 019-043. 3D 4A Guided Step 3D - Check for a pin short circuit to ground. Turn keyswitch OFF. Disconnect the engine harness from the ECM. Disconnect the turbocharger compressor inlet air temperature sensor from the engine harness. check for a pin to ground short. Measure the resistance between the turbocharger compressor inlet air temperature sensor SIGNAL pin in the engine harness ECM connector and ground. Refer to the wiring diagram for connector pin identification.
Turbocharger Number 1 Compressor Inlet Temperature Sensor Circuit - Voltage Be... Page 12 of 14 For general resistance measurement techniques, refer to the Resistance Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360. Greater than 100k ohms? Greater than 100k ohms? A pin to ground short circuit on the SIGNAL line has been detected in the engine harness. Troubleshoot each harness connected in series to determine which contains the shorted signal circuit to ground. Repair or replace the engine harness. Refer to Procedure 019-043. 3E 4A Guided Step 3E - Check for an inactive fault code. Connect all components. Turn keyswitch ON. Connect INSITE electronic service tool. check for the appropriate circuit response after 30 seconds. Use INSITE electronic service tool to read the fault codes. is is
Turbocharger Number 1 Compressor Inlet Temperature Sensor Circuit - Voltage Be... Page 13 of 14 None. The removal and installation of the connector corrected the failure. 4A Troubleshooting procedures need to be repeated from the beginning. A failure mode should have been detected. 1A Guided Step 4 - Clear the fault codes. Guided Step 4A - Disable the fault code. Connect all components. Turn keyswitch ON. Connect INSITE electronic service tool. disable the fault code. Start the engine and let it idle for 1 minute. Use INSITE electronic service tool to verify that the fault code is inactive. Return to the troubleshooting steps or contact a local Cummins Authorized Repair location if all steps have been completed and rechecked.
Turbocharger Number 1 Compressor Inlet Temperature Sensor Circuit - Voltage Be... Page 14 of 14 4B 1A Guided Step 4B - Clear the inactive fault codes. Connect all components. Turn keyswitch ON. Connect INSITE electronic service tool. clear the inactive fault codes. Use INSITE electronic service tool to erase the inactive fault codes. All fault codes cleared? Repair complete All fault codes cleared? Troubleshoot any remaining active fault codes. Appropriate troubleshooting steps Last Modified: 28-Jan-2004 Copyright 2004 Cummins, Inc. All rights reserved