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HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN PASSENGER EXTENDED, 5.0 MREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 215 (ENGINE CONTROLS SELF-DIAGNOSTICS - 3.4L)DIAGNOSTIC TESTSDTC P0116: ECT SENSOR CIRCUIT PERFORMANCEDIAGNOSTIC PROCEDURES
2001 Chevrolet Chevy Express G2500, Van Passenger Extended, 5.0 M

Diagnostic Procedures

2001 Chevrolet Chevy Express G2500, Van Passenger Extended, 5.0 MSECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
    2. NOTE: The cooling fans are commanded ON when certain engine coolant temperature DTCs are set.
  2. Inspect the cooling system coolant level. Is the cooling system low on coolant? If yes, check and repair cause of loss of coolant. If no, go to next step.
  3. Observe and record the ambient air temperature of the vehicle environment using an accurate thermometer. After you complete the action, go to next step.
    4. NOTE: The vehicle needs to have been OFF for at least 8 hours for the ECT and the Intake Air Temperature (IAT) to be at ambient temperature. The vehicle should not have changed environments during this time.
  4. Has the engine been OFF for the specified amount of time? If yes, go to step  7. If no, go to next step.
  5. Remove the Intake Air Temperature (IAT) sensor. Remove the ECT sensor. Place the sensors on a work surface away from any heat source. Allow the sensors to reach the ambient air temperature for 30-60 minutes. After sensors are at the ambient temperature, go to next step.
  6. Connect the IAT sensor to the harness connector, but DO NOT install it. Insulate the sensor from any engine heat source. Connect the ECT sensor to the harness connector, but DO NOT install it. Insulate the sensor from any engine heat source. After action is completed, go to next step.
  7. Turn ignition switch to RUN position. Take a snapshot of the Engine Data List using a scan tool. Review the snapshot data that was taken using the scan tool. Observe the ECT Sensor parameter. Observe the IAT Sensor parameter. Is the difference between the ECT Sensor parameter and the IAT Sensor parameter more than 27°F (15°C)? If yes, go to next step. If no, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article.
  8. Observe the recorded IAT Sensor parameter. Is the difference between the IAT Sensor parameter and the ambient air temperature less than 14°F (8°C)? If yes, go to next step. If no, go to step  10.
  9. Observe the recorded ECT Sensor parameter. Is the difference between the ECT Sensor parameter and the ambient air temperature less than 14°F (8°C)? If yes, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article. If no, go to step  12.
  10. Disconnect the IAT sensor harness connector. Check for an intermittent and or a poor connection at the IAT sensor. Did you find and correct the condition? If yes, go to step  25. If no, go to next step.
    11. NOTE: DO NOT hold the IAT sensor by the probe.
  11. At the sensor, measure the resistance between the IAT signal and the IAT low reference terminals using a DMM and record the value. Observe the recorded ambient air temperature. Compare the resistance measurement of the IAT sensor to the ambient air temperature using the Temperature vs. Resistance table. See TEMPERATURE VS. RESISTANCE  table. Is the resistance measurement of the IAT sensor within the specified range? If yes, go to step  14. If no, go to step  22.
  12. Disconnect the ECT sensor harness connector. Check for the following conditions:
    • An ECT sensor leaking engine coolant internally through the sensor.
    • Corrosion on the ECT sensor terminals.
    • Corrosion on the ECT harness connector terminals.

    Did you find and correct the condition? If yes, go to step  25. If no, go to next step.

    13. NOTE: DO NOT hold the ECT sensor by the probe.
  13. At the sensor, measure the resistance between the ECT signal and the ECT low reference terminals using a DMM and record the value. Observe the recorded ambient air temperature. Compare the resistance measurement of the ECT sensor to the ambient air temperature using the Temperature vs. Resistance table. See TEMPERATURE VS. RESISTANCE  table. Is the resistance measurement of the ECT sensor within the specified range? If yes, go to step  15. If no, go to step  23.
  14. Measure the voltage from the IAT signal circuit to a good ground using a DMM. Is the voltage 4.8-5.2 volts? If yes, go to step  16. If no, go to step  17.
  15. Measure the voltage from the ECT signal circuit to a good ground using a DMM. Is the voltage 4.8-5.2 volts? If yes, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article. If no, go to step  19.
    16. NOTE: All electrical components and accessories must be turned OFF. Performing this step will disable the diagnostic for 8 hours.
  16. Turn ignition switch to OFF position for 90 seconds to allow the control modules to power down. Measure the resistance from the low reference circuit of the IAT sensor to a good ground using a DMM. Is the resistance less than 5 ohms? If yes, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article. If no, go to step  18.
  17. Check the IAT signal circuit for a high resistance. Did you find and correct the condition? If yes, go to step  25. If no, go to step  20.
  18. The IAT low reference circuit for a high resistance. Did you find and correct the condition? If yes, go to step  25. If no, go to step  20.
  19. Check the ECT signal circuit for a high resistance short to ground. Did you find and correct the condition? If yes, go to step  25. If no, go to step  21.
  20. Check for an intermittent and for a poor connection at the Powertrain Control Module (PCM). Did you find and correct the condition? If yes, go to step  25. If no, go to step  24.
  21. Check for shorted terminals and poor connections at the PCM. Did you find and correct the condition? If yes, go to step  25. If no, go to step  24.
  22. Replace the IAT sensor. After repair, go to step  25.
  23. Replace the ECT sensor. After repair, go to step  25.
  24. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  25. Reassemble the vehicle as necessary. After repair, go to next step.
    26. NOTE: This DTC will not run without the ignition being OFF for at least 8 hours.
  26. Clear the DTCs using a scan tool. Turn ignition switch to OFF position for 8 hours. Start the engine. Operate the vehicle within the Conditions For Running. See CONDITIONS FOR RUNNING . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  27. Using the scan tool, observe the stored information in CAPTURE INFO. Are there any DTCs that have not been diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay at this time.
TEMPERATURE VS. RESISTANCE

°F (°C) (1) Ohms
302 (150) 47
284 (140) 60
266 (130) 77
248 (120) 100
230 (110) 132
212 (100) 177
194 (90) 241
176 (80) 332
158 (70) 467
140 (60) 667
122 (50) 973
113 (45) 1188
104 (40) 1459
95 (35) 1802
86 (30) 2238
77 (25) 2796
68 (20) 3520
59 (15) 4450
50 (10) 5670
41 (5) 7280
32 (0) 9420
23 (-5) 12,300
14 (-10) 16,180
5 (-15) 21,450
-4 (-20) 28,680
-22 (-30) 52,700
-40 (-40) 100,700
(1) Values are approximate.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.