P1290: Cylinder Head Temp Sensor Low Input

Definition

The OBD2 code P1290 indicates that the cylinder head temperature sensor is providing a low voltage input, which may suggest a malfunction in the sensor or its circuit

Common causes

Faulty cylinder head temperature sensor
Damaged wiring or connectors
Poor electrical connections
Short circuit in the sensor circuit
Open circuit in the sensor circuit
Faulty engine control module (ECM)

Common misdiagnoses

Faulty Cylinder Head Temperature Sensor
Wiring Issues or Short Circuits
Engine Coolant Temperature Sensor Malfunction
Engine Control Module (ECM) Issues
Thermostat Problems
Air Intake Temperature Sensor Faults
Fuel System Issues
Ignition System Problems

Troubleshooting steps

1. Check the Code

Use an OBD-II scanner to confirm the P1290 code and check for any additional codes that may provide more context
2. Visual Inspection
3. Inspect the wiring and connectors leading to the cylinder head temperature sensor for any signs of damage, corrosion, or loose connections
4. Look for any frayed wires or broken connectors that could affect the sensor's signal
5. Test the Sensor
6. Disconnect the cylinder head temperature sensor and test its resistance with a multimeter. Compare the readings to the manufacturer's specifications
7. If the resistance is outside the specified range, the sensor may be faulty and should be replaced
8. Check the Ground
9. Ensure that the ground connection for the cylinder head temperature sensor is secure and free of corrosion. A poor ground can lead to low input signals
10. Inspect the ECM
11. If the sensor and wiring are in good condition, the issue may lie with the engine control module (ECM). Check for any software updates or recalls related to the ECM
12. If possible, test the ECM with a known good sensor to see if the problem persists
13. Check for Short Circuits
14. Use a multimeter to check for short circuits in the wiring harness. A short to ground can cause a low input signal
15. Clear the Code
16. After performing any repairs or replacements, clear the code using the OBD-II scanner and take the vehicle for a test drive to see if the code returns
17. Monitor Live Data
18. Use the OBD-II scanner to monitor live data from the cylinder head temperature sensor while the engine is running. This can help determine if the sensor is functioning correctly
19. Consult Repair Manual
20. Refer to the vehicle's repair manual for specific testing procedures and specifications related to the cylinder head temperature sensor
21. Seek Professional Help
22. If the issue persists after performing these steps, it may be best to consult a professional mechanic for further diagnosis and repair. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P1290 code

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check the Code

2. Visual Inspection

3. Inspect the wiring and connectors leading to the cylinder head temperature sensor for any signs of damage, corrosion, or loose connections

4. Look for any frayed wires or broken connectors that could affect the sensor's signal

5. Test the Sensor

6. Disconnect the cylinder head temperature sensor and test its resistance with a multimeter. Compare the readings to the manufacturer's specifications

7. If the resistance is outside the specified range, the sensor may be faulty and should be replaced

8. Check the Ground

9. Ensure that the ground connection for the cylinder head temperature sensor is secure and free of corrosion. A poor ground can lead to low input signals

10. Inspect the ECM

11. If the sensor and wiring are in good condition, the issue may lie with the engine control module (ECM). Check for any software updates or recalls related to the ECM

12. If possible, test the ECM with a known good sensor to see if the problem persists

13. Check for Short Circuits

14. Use a multimeter to check for short circuits in the wiring harness. A short to ground can cause a low input signal

15. Clear the Code

16. After performing any repairs or replacements, clear the code using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

17. Monitor Live Data

18. Use the OBD-II scanner to monitor live data from the cylinder head temperature sensor while the engine is running. This can help determine if the sensor is functioning correctly

19. Consult Repair Manual

20. Refer to the vehicle's repair manual for specific testing procedures and specifications related to the cylinder head temperature sensor

21. Seek Professional Help

22. If the issue persists after performing these steps, it may be best to consult a professional mechanic for further diagnosis and repair. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P1290 code