CHECK ECM GROUND HARNESS.

1) Connect all connectors.

2) Turn the ignition switch to ON.

3) Measure the voltage between ECM and chassis ground.

Connector & terminal

Euro 4 model

(B134) No. 6 (+) — Chassis ground (−):
(B135) No. 3 (+) — Chassis ground (−):
(B135) No. 4 (+) — Chassis ground (−):
(B137) No. 1 (+) — Chassis ground (−):
(B137) No. 6 (+) — Chassis ground (−):
(B137) No. 7 (+) — Chassis ground (−):

Euro 5 model

(B135) No. 3 (+) — Chassis ground (−):
(B135) No. 4 (+) — Chassis ground (−):
(B135) No. 5 (+) — Chassis ground (−):
(B136) No. 6 (+) — Chassis ground (−):
(B137) No. 6 (+) — Chassis ground (−):
(B137) No. 7 (+) — Chassis ground (−):

QUESTION

Is the voltage less than 1 V?

Yes No

Repair the poor contact of ECM connector.

Repair the following item.

• Open circuit in ground circuit

• Further tightening of the engine ground terminal

• Poor contact of coupling connector