Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Coolant Temperature Sensor (CTS) & MAT Sensor
1987 Jeep Cherokee LimitedSECTION Coolant Temperature Sensor (CTS) & MAT Sensor
- Disconnect the electrical connector from the sensor. Using a high impedance, digital volt/ohmmeter, measure sensor resistance. If sensor resistance is not as specified, replace sensor. Refer to the CTS & MAT SENSOR TEMPERATURE-TO-RESISTANCE VALUE table.
- Test electrical harness resistance of both sensors by testing between ECU harness connector "D-3" and sensor connector. Also test between sensor connector and ECU harness connector "C-10" ("C-8" on MAT sensor). Repair wire if open circuit is detected. Repair MAT sensor wiring harness if resistance is greater than one ohm.
CTS & MAT SENSOR TEMPERATURE-TO-RESISTANCE VALUE
| °F(°C) | Ohms |
|---|---|
| 212 (100) | 185 |
| 160 (71) | 450 |
| 100 (38) | 1600 |
| 70 (21) | 3400 |
| 40 (4) | 7500 |
| 20 (-7) | 13,500 |
| 0 (-18) | 25,000 |
| -40 (-40) | 100,700 |
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.