Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For circuit identification and wiring diagram, see CHEROKEE wiring diagram in WIRING DIAGRAMS article.
Note. P0118: ECT SENSOR VOLTAGE TOO HIGH is monitored with ignition on and battery voltage more than 10.4 volts. DTC may be stored in Powertrain Control Module (PCM) when PCM senses Engine Coolant Temperature (ECT) sensor voltage is more than 4.98 volts for more than 3 seconds. Possible causes are: defective ECT sensor, defective PCM, defective connectors or defective wiring.
- Turn ignition on, with engine off. Using scan tool, read ECT sensor voltage. If voltage is more than 4.5 volts, go to next step. If voltage is 4.5 volts or less, go to step 6).
- Turn ignition off. Disconnect ECT sensor connector. Clean and/or repair connector as necessary. Connect a jumper wire between ground and ECT sensor connector, sensor ground circuit (Brown/Yellow wire). Turn ignition on, with engine off. Using scan tool, read ECT sensor voltage. If voltage is less than one volt, repair open sensor ground circuit. Perform TEST VER-5A. If voltage is one volt or more, go to next step.
- Turn ignition off. Ensure ECT sensor connector is still disconnected. Connect a jumper wire between ECT sensor connector, signal circuit (Tan/Black wire) and sensor ground circuit (Brown/Yellow wire). Turn ignition on, with engine off. Using scan tool, read ECT sensor voltage. If voltage is less than one volt, replace ECT sensor. Perform TEST VER-5A. If voltage is one volt or more, go to next step.
- Turn ignition off. Ensure ECT sensor connector is still disconnected. Disconnect PCM connectors. PCM is located in engine compartment. See PCM LOCATION table under SYSTEM DIAGNOSTICS. Clean and/or repair connectors as necessary. Using an ohmmeter, check resistance of ECT sensor signal circuit (Tan/Black wire) between ECT sensor and PCM. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open signal circuit. Perform TEST VER-5A.
- At this time, PCM is assumed to be defective. Replace PCM. Perform TEST VER-5A.
- Ensure ignition is on, with engine off. Wiggle ECT sensor connector and wiring harness while monitoring ECT sensor voltage. If voltage changes while wiggling connector and wiring harness, repair connector or wiring harness where wiggling caused voltage to change. Perform TEST VER-5A. If voltage does not change, go to next step.
- Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. Perform TEST VER-5A. If connectors and wiring harness are okay, test is complete.