Connecting Test Equipment and Reading Diagnostic Trouble Codes

TESTING WITH IMPULSE COUNTER SCAN TOOL:

Connection Diagram - Impulse Counter Scan Tool:

Image Reference:
013 Impulse counter scan tool
075 Impulse counter scan tool adaptor
X11/4 Data link connector (DTC readout, 38-pole)

- The (Diagnostic Trouble Code) DTC readout displays only those DTC's present at the time of diagnosis. It cannot store previous DTC's in memory.
- If one or more faults are displayed by the DTC readout, then these are to be eliminated and the DTC test repeated. This ensures that all DTC's which are recorded by the impulse counter scan tool have been eliminated.
- If the DTC readout indicates no fault, but a complaint still exists, a component tolerance deviation may exist, i.e. low ohm value at a sensor. Since such a deviation cannot be detected via the DTC readout, the system must be checked thoroughly using the socket box and multimeter.

1. Connect the impulse counter scan tool according to the connection diagram. The LED "U Batt" must be illuminated.

- If the LED "U BATT" does not illuminate, first check the fuse, then check for voltage between socket 1 of the on-board diagnostic connector and the positive terminal of the battery. If the voltage is not between 11-14 volts, check for an open circuit or loose ground connection. Test for voltage between socket 7 and socket 1 of the diagnostic connector. The voltage should be 6 - 12 volts.

2. Turn the ignition to the "ON" position.

3. Depress the start button for 2 - 4 seconds.

- Fault codes will be indicated by the number in the impulse counter display window. Take note of the impulse display number. (See image above for list of DTC's, also Diagnostic Trouble Code (DTC) Descriptions and Test Procedures)
- Faults are displayed in ascending order.
- The number 1 indicates that no faults are stored in memory.

4. Repeat step 3 until all faults are indicated. After all fault codes have been displayed, pushing the start button again for 2 - 4 seconds will repeat the fault code readout sequence.

5. Eliminate all noted faults (DTC readouts) and switch the ignition on and off.

NOTE: During the DTC test the light emitting diode in the fresh air/recirculated air switch flashes.