CHECK POWER SUPPLY CM.

1) Disconnect the engine ECM connector.

2) Depress the brake pedal, and press the push button ignition switch.

3) Using a tester, measure the voltage between the power supply CM and chassis ground.

Connector & terminal

(B420) No. 12 (+) — Chassis ground (−):

QUESTION

Does the voltage change from less than 1 V → 2 V or more?

Yes No

Perform fault diagnosis for the engine system.

Replace the power supply CM.