Test DA: Step 10

10) Code 51, 54 or 58: Induce Opposite Code (61, 64 or 68)  Code 51 (ECT), 54 (ACT or VAT) and 58 (VAT) indicate that the corresponding sensor signal is greater than the Self-Test maximum. Maximum signal voltage for ECT and ACT sensors is 4.6 volts. Maximum signal voltage for VAT sensors is 3.5 volts. Possible causes for excess voltage signals are:

• Temperature too low (VAT)
• Open circuit in vehicle harness (ACT or ECT)
• Faulty connection
• Faulty sensor
• Faulty ECA

Turn key off and wait 10 seconds. Disconnect suspect temperature sensor. Connect a jumper wire between the sensor signal circuit and the SIG RTN circuit at the temperature sensor vehicle harness connector. Perform KOEO Self-Test. If Code 61, 64 or 68 is displayed, replace suspect sensor. Remove jumper wire, reconnect vehicle harness, and repeat QUICK TEST. If Code 61, 64 or 68 is not displayed, remove jumper wire and go to next step.