Without Scan Tool

DIAGNOSTIC CODE INTERPRETATION
The Electronic Control Module (ECM) monitors operation of the emission control system. Some components are monitored continuously, others only during specified operating conditions. When the ECM detects a malfunction lasting longer than a specified period of time the ECM will generate a trouble code that can be read at the diagnostic connector.

- There are fourteen diagnostic items (including normal operation) that will generate diagnostic codes.

- The trouble codes are erased when the vehicle battery is disconnected for more than ten seconds.

NOTE: If the Oxygen Sensor is disconnected during engine operation for testing purposes a code will be stored and must be cleared after the test is complete.

To test for oxygen sensor codes drive the vehicle a significant distance and check for diagnostic codes before turning the ignition off. Do not however disconnect the battery with the ignition ON or the engine running as permanent damage to the vehicle electronic components may result.

If multiple codes have been set, the codes will be sent sequentially, in ascending order, with a 2 second pause between codes.

READING DIAGNOSTIC CODES

Data Link Connector (DLC):

1. Ground Data Link Connector terminal # 1.

Malfunction Indicator (MIL) Light Location:

Diagnostic Trouble Code Output:

2. Set the ignition switch to "ON", the Malfunction Indicator (check engine) Lamp will illuminate for a particular duration and a certain number of times.

EXAMPLES:
Code 13
- The Lamp will illuminate one time for approximately 0.5 second. This will represent one unit of ten. There will be approximately a one second delay and then the Lamp will illuminate three times for approximately 0.2 seconds with 0.1 second delay between deflections. This will represent three units of one.

Code 23
- The Lamp will illuminate two times for approximately 0.5 second with approximately 0.3 second delay between deflections. This will represent two units of ten. There will be approximately a one second delay and then the Lamp will illuminate three times for approximately 0.2 seconds with 0.1 second delay between deflections. This will represent three units of one.

3. Refer to the Trouble Code to Fault Message Conversion Chart to determine which circuit is outside of the acceptable parameters.
4. Test and repair the cause as necessary.
5. Clear the trouble codes by disconnecting the vehicle battery negative terminal for 16 seconds or longer.
6. Road test the vehicle and check for new codes that may have been set.