Diagnosis codes are held in memory and may be displayed by grounding the proper terminals at the diagnostic connector or check connector. The system should be interrogated for stored codes before any disconnection of the battery cables; once disconnected, the stored codes will be lost. Certain conditions must be met before the codes will be transmitted from the ECU. The initial conditions are:
If any of the initial conditions are not met, the ECU will note a problem and display a switch condition code when the diagnostic circuit is grounded.Diagnostic Connector Locations
See Figure 1
On all equipped vehicles the check connector (near the ignition coil) or diagnostic connector are located under the hood in the engine area on the shock tower (passenger side) or near the junction or relay block (driver's side). A small plastic cap covers the check connector terminals and hinged plastic cap covers the diagnostic connector. Each terminal is mark inside the diagnostic cap cover for proper identification.
- Check that the initial conditions are met.
- Turn the ignition switch ON but do not start the engine.
- At the diagnostic connector or check connector, use a jumper wire to connect terminals T and E 1 .
- Observe the CHECK ENGINE warning lamp on the dashboard; read the code(s) based on the number and rate of flashes.
- If the system is operating normally, with no codes stored, the warning lamp will flash on/off in a constant, unchanging pattern. This is the System Normal signal; the ECU is acknowledging the request for codes but has nothing to report.
- If malfunction codes are stored, the light will blink every 1 / 2 -second. The first number of blinks will indicate the first digit of a 2-digit code. After a 1 1 / 2 second pause, the second digit will be transmitted. If there is more than one code stored, they will be separated by a 2 1 / 2 -second pause. After all stored codes have been transmitted, the cycle will begin again after a 4 1 / 2 second pause. The codes will continuously transmit until the jumper wire is disconnected. Even when transmission has stopped, the codes remain in memory until the memory is cleared.
If more than one code is stored, the codes will be transmitted in numerical order from lowest to highest. The order of the codes does not indicate the order of fault occurrence.
- Record the codes as they are received.
- Disconnect the diagnostic jumper; switch the ignition OFF .
Stored codes will remain in memory until cleared. The correct method of clearing codes is to turn the ignition switch OFF , then remove the EFI 15A fuse for at least 30 seconds. The time required will be longer in cold weather.
Disconnecting the negative battery cable will also clear the memory but is not recommended due to other on-board memories being cleared as well. Once the system power is restored, re-check for stored codes. Only the System Normal indication should be present. If any other code is stored, the clearing procedure must be repeated or the old code will be stored with any new ones.
After repairs, it is recommended to clear the memory before test driving the vehicle. Upon returning from the drive, interrogate the memory; if the original code is again present, the repair was unsuccessful.