Chrysler ECU Computer Code 22: Coolant temperature sensor out of range

by Bob O’Neill and Bob Lincoln

Code 22 is set when the computer senses the Coolant Temperature Sensor is out of range (not returning a realistic voltage). The power limited light will be lit, the car will enter limp mode, and the radiator fan will be left on; the charge temperature will be temporarily used as an indication of the coolant temperature.

On 1985 models code 22 is set when the sensor output is less than 0.157V or greater than 3.76V
On 1986 and later models code 22 is set when the sensor output less than 0.51V or greater than 4.96V

Possible Reasons for Fault Code 22

Defective coolant temperature sensor – To check for a defective sensor, use an ohm meter and measure across the pins of the sensor. The sensor is located on the right side of the water box on cars with 2.2 and 2.5 liter engines.

For 1985 models, at 77° F, the sensor should measure 5,290 ohms to 5,610 ohms.

For 1986 and later models, at 77° F, the sensor should measure 9,120 ohms to 10,880 ohms.

Poor wiring or connection - Read the page ‘How to troubleshoot drivability issues’. Check the wiring and connections between the sensor and the logic module.  Check the harness from the sensor to the computer. Inspect every connector. Clean and re-grease the connectors with dielectric grease.   When setting ignition timing it may be necessary to disconnect the sensor from the harness.

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