Test DA: Step 1

1) Code 21, 24 or 28: Check Installation & Operation of Temperature Sensor  Codes 21 (ECT), 24 (ACT or VAT) and 28 (VAT) indicates that the corresponding sensor is out of Self-Test range. Correct range for measurement is .3 to 3.5 volts. Possible causes are:

• Low Ambient Temperature (Less Than 50°F)
• Low Coolant Level
• Faulty Harness Connector
• Faulty Sensor

If vehicle is a no start, go to step 3). If vehicle stalls or starts and dies, go to TEST S, step 1). Run engine for 2 minutes at 2000 RPM. Ensure upper radiator hose is hot and pressurized. Repeat QUICK TEST. If Codes 21, 24 or 28 are present, go to next step. If not, service other codes as necessary.