Page 411 of 801
YH4
GRAND
VITARA
AUTOMATIC TRANSMISSION (4 A / T) 7B1-9
H25 Engine
1. PCM (ECM)
2. VSS
3. CMP sensor
4. TP sensor
5. ECT sensor
6. Brake pedal switch
7. A / T input speed sensor
8. A / T output speed sensor9. Transmission range switch
10. Shift solenoid-A
11. Shift solenoid-B
12. TCC solenoid
13. Data link connector
14. Cruise control module
15. ªPOWERº lamp
16. ªO / D OFFº lamp17. MIL
18. O / D cut switch
19. P / N change switch
20. 4WD low switch
21. Main relay
22. Ignition switch
23. Battery
24. PCM (ECM) connector terminal
(viewed from harness side) Bl / Y
Bl / G
W
OrC51-1-16
C51-1-8
C51-1-10
C51-1-9
12V
Page 433 of 801
YH4
GRAND
VITARA
AUTOMATIC TRANSMISSION (4 A / T) 7B1-31
Brake pedal Released Depressed
Voltage 0 VBattery
voltage
DIAGNOSTIC FLOW TABLE A-1 (NO TCC LOCK-UP OCCURS)
SYSTEM DESCRIPTION
PCM turns TCC solenoid OFF under any of the following conditions.
Brake pedal switch: ON
4WD LOW switch: ON
Cruise control module: TCC OFF command signal is output (if equipped).
ECT: ECT < 30C (86F)
TROUBLESHOOTING
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 person, a driver and tester, on a level road.
STEPACTIONYESNO
1Was ªAUTOMATIC TRANSMISSION
DIAGNOSTIC FLOW TABLEº performed?Go to Step 2.Go to ªAUTOMATIC
TRANSMISSION
DIAGNOSTIC FLOW
TABLEº.
2ECT check:
(1) Warm up engine to normal operating
temperature.
(2) Check ECT using scan tool.
Is ECT more than 30C (86F)?Go to Step 3.Faulty ECT sensor, its
circuit or engine cooling
system.
If OK, substitute a known-
good PCM and recheck.
3Perform running test under the following
conditions and check voltage between
C51-1-8 (G16 / J20 engines) or C51-1-2 (H25
engine) terminal of PCM coupler and ground.
Normal mode in ªDº range.
Transfer ª2Hº position.
Cruise control is not operated (if equipped).
Brake pedal released.
Drive vehicle with TCC ON condition
referring to ªTCC lock-up diagramº in
this section.
Is it battery voltage?Faulty TCC solenoid
valve, its circuit or
transmission.Go to Step 4.
4Is vehicle equipped with H25 engine?Go to Step 5.Go to Step 6.
5Brake switch signal inspection:
(1) With ignition switch ON, check voltage
between E61-31 terminal of PCM coupler
terminal and ground.
Is the result as specified?Go to Step 6.Faulty brake pedal switch
or its circuit.
If OK, substitute a known-
good PCM and recheck.
Page 434 of 801
YH4
GRAND
VITARA
7B1-32 AUTOMATIC TRANSMISSION (4 A / T)
Transfer gear
positionª4Lº or ªNº ª4Hº or ª2Hº
Voltage 0 VBattery
voltage
STEPACTIONYESNO
6ª4WD LOWº switch signal inspection:
(1) With ignition switch ON, check voltage
between C51-1-26 (G16 / J20 engines) or
C51-1-5 (H25 engine) terminal of PCM
coupler and ground.
Is the result as specified?Go to Step 7.Faulty ª4WD LOWº
switch or its circuit.
If OK, substitute a known-
good PCM and recheck.
7Is vehicle equipped with cruise control
system?Go to Step 8.Substitute a known-good
PCM and recheck.
8Cruise control signal inspection:
(1) With ignition switch ON, check voltage
between E61-35 (G16 / J20 engines) or
E61-3 (H25 engine) terminal of PCM
coupler and ground.
Is it battery voltage?Substitute a known-good
PCM and recheck.Faulty cruise control
module or its circuit.
If OK, substitute a known-
good PCM and recheck.
Page 435 of 801
YH4
GRAND
VITARA
AUTOMATIC TRANSMISSION (4 A / T) 7B1-33
O / D cut
switchOFF ON
VoltageBattery
voltage0 V
DIAGNOSTIC FLOW TABLE A-2 (NO GEAR SHIFT TO O / D)
SYSTEM DESCRIPTION
PCM does not shift to O / D gear under any of the following conditions.
O / D cut switch: ON
4WD LOW switch: ON
Cruise control module: O / D OFF command signal is output (if equipped).
ECT: ECT < 30C (86F)
TROUBLESHOOTING
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 person, a driver and tester, on a level road.
STEPACTIONYESNO
1Was ªAUTOMATIC TRANSMISSION
DIAGNOSTIC FLOW TABLEº performed?Go to Step 2.Go to ªAUTOMATIC
TRANSMISSION
DIAGNOSTIC FLOW
TABLEº.
2ECT check:
(1) Warm up engine to normal operating
temperature.
(2) Check ECT using scan tool.
Is ECT more than 30C (86F)?Go to Step 3.Faulty ECT sensor,
its circuit or engine
cooling system.
If OK, substitute a known-
good PCM and recheck.
3Perform running test under the following
conditions and check voltage between
C51-1-2 (G16 / J20 engines) or C51-1-6 (H25
engine) terminal of PCM coupler and ground,
C51-1-1 terminal of PCM coupler and ground.
O / D cut switch OFF (ªO / D OFFº lamp OFF).
Normal mode in ªDº range.
Transfer ª2Hº position.
Cruise control is not operated (if equipped).
Drive vehicle with 4th gear condition
referring to ªGear shift diagramº in this
section.
Is each voltage about 0 V?Faulty shift solenoid
valve, its circuit or
transmission.ªGº wire or ªG / Rº wire
shorted to power circuit.
If OK, go to Step 4.
4O / D cut switch signal inspection:
(1) With ignition switch ON, check voltage
between E61-33 (G16 / J20 engines) or
E61-14 (H25 engine) terminal of PCM
coupler and ground.
Is the result as specified?Go to Step 5.Faulty O / D cut switch or
its circuit.
If OK, substitute a known-
good PCM and recheck.
Page 436 of 801
YH4
GRAND
VITARA
7B1-34 AUTOMATIC TRANSMISSION (4 A / T)
Transfer gear
positionª4Lº or ªNº ª4Hº or ª2Hº
Voltage 0 VBattery
voltage
STEPACTIONYESNO
54WD LOW switch signal inspection:
(1) With ignition switch ON, check voltage
between C51-1-26 (G16 / J20 engines) or
C51-1-5 (H25 engine) terminal of PCM
coupler and ground.
Is the result as specified?Go to Step 6.Faulty 4WD LOW switch
or its circuit.
If OK, substitute a known-
good PCM and recheck.
6Is vehicle equipped with cruise control
system?Go to Step 7.Substitute a known-good
PCM and recheck.
7Cruise control signal inspection:
(1) With ignition switch ON, check voltage
between E61-35 (G16 / J20 engines) or
E61-3 (H25 engine) terminal of PCM
coupler and ground.
Is it battery voltage?Substitute a known-good
PCM and recheck.Faulty cruise control
module or its circuit.
If OK, substitute a known-
good PCM and recheck.
