D3 Check ECU Ground

- Install Breakout Box (BOB). Using the Breakout Box For Circuit Checks

- Inspect ground stud for corrosion.

- Measure resistance between BOB Pins 1 and 14 and chassis ground.

- Is resistance less than 0.5 ohm?

YES -- Replace ECU. GO to D4. D4 Verify Concern Is Resolved

NO -- Service high resistance in ECU ground circuit. Go to D4. D4 Verify Concern Is Resolved