AT/Automatic Transmission — Trouble No. 3 Shift point too high or too low, page 15

AUTOMATIC TRANSMISSION — Electric Control                    AT-15

Trouble No. 3    Shift point too high or too low

Warm up engine
Coolant temp:  80°C (176°F)
ATF temp:      50 — 80°C (122 — 176°F)

Output diagnostic code
(See page AT-8)

No indicate

Connect a voltmeter to the DG
terminal and body.
Does DG terminal voltage vary with changes
in throttle opening?

Yes                                  No

Is voltage between ECT ECU terminals
BR and GND as follows?
OV: Brake pedal released
12V: Brake pedal depressed

No  ——→  Brake signal faulty

Yes

•  Computer power source and earth faulty
•  Throttle position signal faulty
•  DG terminal wire open or short

Check voltage between ECT ECU terminals
PWR and GND.

Power Pattern:  12V      OK  ——→  Faulty ECT ECU
Normal Pattern:  1V             Faulty transmission
                     No  ——→  Faulty pattern select switch system

Diagnosis code  ——→  Proceed to trouble No. 1 (AT-12)