Pinpoint Test Q
Enter this pinpoint test only when directed from KEY ON, ENGINE RUNNING or KEY ON, ENGINE OFF SELF-TEST. This pinpoint test is intended to diagnose only the ECA and harness circuits (signal return, STO, STI, and ground).
- Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector and inspect for damage. Service as necessary. Install Breakout box, leaving ECA disconnected. Set DVOM to 200-ohm scale. Measure resistance between SELF-TEST input at SELF-TEST single pin connector and test pin 48 at Breakout box. If less than 5 ohms, go to Step 2). If greater than 5 ohms, correct open in circuit.
- Install Breakout box. Set DVOM to 200-ohm scale. Measure resistance between SELF-TEST output at SELF-TEST connector and test pin 17 at Breakout box. If less than 5 ohms, go to Step 3). If greater than 5 ohms, correct open in circuit.
- Install Breakout box. Turn key off. Measure resistance between EGO ground on engine and test pin 49 at Breakout box. If less than 5 ohms, go to Step 4). If greater than 5 ohms, check and service EGO sensor ground wire or open circuit.
- Install Breakout box. Set DVOM on 200,000-ohm scale. Measure resistance between SELF-TEST output at SELF-TEST connector and engine block ground. If resistance is greater than 10,000 ohms, replace ECA and repeat QUICK TEST. If not, service shorts to ground and repeat QUICK TEST. See Fig 1.