Transmission Control Systems

TROUBLE CODE 22
MASS AIR FLOW SIGNAL

Diagnosis
Input signal circuit of Transmission Control Module (TCM) from Engine Control Module (ECM) is open or shorted.












1. Check Trouble Code on Engine side.
Using Subaru Select Monitor or 0BD-II General Scan Tool, check trouble code of Mass Air Flow Sensor on Engine side.

2. Check harness connector between TCM and ECM.
a. Turn Ignition Switch to "OFF".
b. Disconnect connectors from TCM and ECM.






c. Measure resistance of harness connector between TCM and ECM.
Connector & Terminal / Specified Resistance:
(B54) No. 9 - (B84) No. 35 / 1 Ohm, or less.






d. Measure resistance of harness connector between TOM and body to make sure that circuit does not short.
Connector & Terminal / Specified Resistance:
(B54) No. 9 - Body / 1 M-Ohms, or more.

3. Check input signal for TCM.
a. Connect connectors to TCM and ECM.
b. Start the Engine. (Engine idling after warm-up)






c. Measure signal voltage between TCM connector terminal and body.
Connector & Terminal / Specified Voltage:
Engine warm-up; (B54) No. 9 - Body / 0.55 ± 0.25 Volts.

Using Subaru Select Monitor






1. Connect connectors to TCM and ECM.
2. Turn Ignition Switch to "OFF".
3. Connect the Subaru Select Monitor to Data Link Connector.
4. Turn Ignition Switch to "ON" and Subaru Select Monitor switch to "ON".
5. Start and warm-up the Engine.
6. Read data on Subaru Select Monitor.
7. Designate mode using function key.
Function mode: F15

Specified Data:
0.55 ± 0.25 Volts (Engine warm-up).