ECM Power and Ground Supply

DIAGNOSTIC CHART

Diagnostic Chart:

CHECK MAIN RELAY

Main Relay:

1. Turn ignition OFF.
2. Remove main relay.
3. Connect battery to relay terminals No. 1 and No. 2.
4. Measure resistance between relay terminals.

Terminals Resistance
No. 3 - 5 10 ohms max.
No. 4 - 6 10 ohms max.

CHECK POWER SUPPLY CIRCUIT OF ECM

Voltage Check:

1. Install main relay.
2. Unplug ECM connectors.
3. Turn ignition ON.
4. Measure power supply voltage between ECM connector terminals and body.

Connector & Terminal Voltage
(E29) 13 - body 10 V min.
(E29) 26 - body 10 V min.

CHECK ECM GROUND CIRCUIT

Harness Terminals:

1. Turn ignition OFF.
2. Measure resistance of harness connector between ECM and body.

Connector & Terminal Resistance
(E29) 25 - body 10 ohms max.
(E29) 14 - body 10 ohms max.
(E29) 15 - body 10 ohms max.
(E30) 11 - body 10 ohms max.
(E30) 22 - body 10 ohms max.