A/T - Check Trans Lamp ON/Flash Code 37

SOURCE: Isuzu Service News

TITLE: A/T Flash Code 37

APPLIES TO: 92-95 Rodeo and Trooper

SERVICE TIP:

Complaint:

Check transmission light on, code 37 stored. A/T Code 37 Serial Communications Error

Correction:

1. Inspect the serial communication line for opens or shorts to ground.
2. Voltage drop the TCM and ECM grounds.
3. Monitor voltage on the serial communication line at the ALDL, the voltage should be around 5-volts and should be pulled low just before a shift if the TCM is communicating with the ECM.
4. Check the ability of the ecm and icm to control ignition timing.
5. Remove any aftermarket installations that are either wired into the TCM, serial communications circuit or radio transmitters/alarms, cellular phones, etc. near the suspect circuits.
6. Confirm with the customer if the situation occurs on a suspect driving route near, large suspension bridges, military bases, airports, or radio stations, these are environmental concerns and shielding the controller and lines may help, but under the most severe environmental conditions, there may be no cure other than modifying driving routes.