DTC 23 MASS AIR FLOW SIGNAL

DTC 23 MASS AIR FLOW SIGNAL

CHECK ENGINE GROUND TERMINALS AND GROUND CIRCUIT OF ECM.

Is there any trouble?

Yes

Repair the ground terminal and/or ground circuit of ECM.

No

CHECK HARNESS CONNECTOR BETWEEN TCM AND ECM.

Turn the ignition switch to OFF.

Disconnect the connectors from TCM and ECM.

Measure the resistance of harness between TCM and ECM connector.

Connector & terminal

(B54) No. 1 — (B135) No. 28:

Is the resistance less than 1 Ω?

Yes

No

Repair the open circuit in harness between TCM and ECM connector.

CHECK HARNESS CONNECTOR BETWEEN TCM AND ECM.

Measure the resistance of harness between TCM connector and chassis ground.

Connector & terminal

(B54) No. 1 — Chassis ground:

Is the resistance more than 1 MΩ?

Yes

No

Repair the short circuit in harness between TCM and ECM connector.

CHECK INPUT SIGNAL FOR TCM USING Vehicle Diagnostic Interface.

Connect the connectors to TCM and ECM.

Connect the Vehicle Diagnostic Interface to data link connector.

Start the engine and turn the Vehicle Diagnostic Interface switch to ON.

Warm-up the engine until engine coolant temperature is above 80°C (176°F).

Idle the engine.

Read the data of mass air flow sensor signal using Vehicle Diagnostic Interface.

•	Display shows the mass air flow sensor signal value sent from ECM.

Is the value voltage 0.9 — 1.4 V?

Yes

Even if the AT OIL TEMP warning light blinks, the circuit has returned to a normal condition at this time. A temporary poor contact of the connector or harness may be the cause. Repair harness or connector in the TCM and ECM.

No

CHECK POOR CONTACT.

Is there poor contact in intake manifold pressure signal circuit?

Yes

Repair the poor contact.

No

Replace the TCM.