Chart B Flash Code Diagnosis

Chart B:

SIR Wiring Diagram:

DESCRIPTION:

When the ignition switch is first turned "ON", system voltage is applied from fuse #16 to "SIR Indicator High", terminal B9, and to the "INFL REST" warning lamp which is connected to "SIR Indicator Low", terminal A1. Fuse #18 applies system voltage to the "Ignition 1" inputs, terminals A3 and B3. The DERM responds by flashing the "INFL REST" warning lamp 7 to 9 times.

When the engine is being cranked, system voltage is applied from fuse #1 to the DERM at the "Crank" input. The DERM responds by grounding the "SIR Indicator Low" output until system voltage is removed from the "Crank" input. This results in the "INFL REST" warning lamp being "ON" during cranking.

After cranking, the DERM will again flash the "INFL REST" warning lamp 7 to 9 times.

TEST DESCRIPTION: Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test determines whether "Flash Code" diagnostics can be enabled.

2. This test checks for a good ground at the ALDL connector.

3. This test determines whether further diagnosis is required.

4. This test determines whether only history or both current and history codes exist.

5. This test checks for an open in the "Diagnostic Request" circuit.

6. This test checks for a short to B+ in the "Diagnostic Request" circuit.