4-2

Possible Causes

• •Wire 820G not grounded to main ground point on the engine
• •Breaks in harness
• •Damaged pins in ECM connector
• •No voltage present on Wire 820A when ECM is active
• •No or low voltage measured on Wire 754, Wire 752, or Wire 766 to ground when ECM is active
• •Faulty sensor (TTMAP voltage not between 2.4-2.6 VDC with sensor removed)
• •Spark plug wires not fitted correctly or in poor condition
• •No 12 VDC on Wire 14C at coil connector
• •Fuse F2 is blown or missing
• •Relay (IR) is not operational
• •Ignition coil current is above the threshold when the coil is firing
• •Ignition coil current is below the threshold when the coil is firing
• •Ignition coil current is detected when the coils are not firing

Suggested Actions

1. 1Verify Wire 820G is grounded to the main ground point on the engine
2. 2Test and inspect the harness for breaks
3. 3Inspect the ECM connector for damaged pins
4. 4Test wire 820A to ground for 4.5–5 VDC when the ECM is active
5. 5Inspect the ECM plug for damaged pins
6. 6Test each wire (754, 752, 766) to ground for output voltage when the ECM is active (should be 0.5–4.5 VDC)
7. 7Remove and inspect the sensor
8. 8Replace sensor if TTMAP voltage is not between 2.4–2.6 VDC with sensor removed from system and still connected to harness
9. 9Check spark plug wires for fit and condition
10. 10Check each coil connector for 12 VDC on Wire 14C
11. 11Check the F2 fuse to see if it is blown or missing
12. 12Check if the relay (IR) is operational

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