Diagnostic Aids

Using FREEZE FRAME and/or FAILURE RECORDS data may aid in locating an intermittent condition. If DTC cannot be duplicated, this information can be useful in determining how many times since DTC set. Fail Counter and Pass Counter can also be used to determine how many ignition cycles diagnostic reported a pass and/or a fail. Operate vehicle with same FREEZE FRAME conditions (RPM, load, vehicle speed, temperature, etc.) that were noted.

If other DTCs are set that share same ground and/or 5-volt reference circuit, check for faulty connections or wiring. If engine has been allowed to sit overnight, ECT sensor and IAT sensor values should display within a few degrees of each other.

If engine coolant temperature exceeds 140°F (60°C), this indicates engine is capable of reaching proper temperature, but not necessarily in correct amount of time. This test must be repeated on a cold engine, engine coolant and intake air temperature at less than 122°F (50°C) and within 5°F (3°C) of each other, and time required to reach the temperature threshold must be measured.

The engine should reach specified temperature within 8 minutes. If specified temperature is not reached within specified time, check cooling system.

Check for intermittent problems (i.e., poor connections, rubbed through wire insulation or broken wire inside its insulation). See appropriate TROUBLE SHOOTING - NO CODES article.