Powertrain Controls - ECM/PCM

Code 36 Diagnostic Chart:

Transaxle Control Circuit Diagram:

CIRCUIT DESCRIPTION:
The 4T60 E transaxle is an electronically shifted transaxle. Within the transaxle are 4 solenoids.
Solenoid "A" is used for 1st and 4th gear operation. Solenoid "B" is also used for 1st gear as well as 2nd gear operation. The other two solenoids are for TCC operation only. We will deal with gear operation here only.

When the ignition switch is turned "ON", both solenoid "A" and "B" receive 12 volts from CKT 639. Solenoids become energized when the PCM completes the circuit to ground. The PCM will energize both solenoids "A" and "B" for 1st gear until a shift to 2nd gear is commanded. When the vehicle speed and TPS reach calibrated values the PCM will release the ground for solenoid "A" and 2nd gear is engaged. Further increases in speed will result in the PCM releasing the ground for solenoid "B", 3rd gear. In 3rd gear, both solenoids are de-energized. In 4th gear, solenoid "A" is energized.

All PRNDL indications are ignored as far as transaxle shifting is concerned except for manual low gear. If the PRNDL position indicates manual low has been selected, the PCM will keep both solenoids "A" and "B" energized until 5400 rpm, when the PCM will force a shift by de-energizing solenoid "A". Manual 2nd and manual 3rd are controlled hydraulically within the transaxle.

Code 36 will set if:

Solenoid "B" is failed in the "OFF" position, which will cause the transmission to be in 3rd gear, and:
^ Desired gear is 1st.
^ TPS is greater than 3 %.
^ VSS is greater than 5 mph
^ No code 21,22 or 24 present
^ Vehicle speed Vs. engine speed does not indicate 1st gear.
^ above conditions exist for 3.5 seconds.

OR

Solenoid "B" is failed in the "ON" position which will cause the transmission to be in 1st gear and:
^ Desired gear is 4th.
^ PRNDL is in 3rd or 4th.
^ TPS is greater than 10 %.
^ No code 31,21 or 22 present.
Engine speed Vs. vehicle speed does not indicate 4th gear.

Code 36 does not turn on the "Service Engine Soon" light.

NOTE: When code 36 is set, the transaxle will be forced into 3rd gear. If a code 36 is set due to a grounded CKT 1223, you will have 1st, and 2nd gear operation only. If CKT 1223 is open, you will have 3rd and 4th gear operation only. When the fault goes away, you will have normal operation for the balance of the key cycle.