DTC 87

High Ratio Diagnostic Chart:

Shift Solenoid "B" Circuit:

Circuit Description:
The shift solenoids are used inside the valve body to control spool valve position which determines the transmission gear.

Fused ignition power is supplied to solenoid '°B". The PCM/TCM will engage B" by grounding CKT 1223 to energize the solenoid.

Code 87 will set when:
^ Vehicle speed is above 7 mph.
^ TPS is more than 25%.
^ PCM/TCM commands 3rd or 4th gear.
^ Box ratio indicates trans is in 1st or 2nd gear.
^ Conditions met for 6 seconds.



Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.

1. Test one checks the PCM/TCM's ability to ground or control solenoid "B".

2. Test two checks the power supply and CKT 1223.

3. Test three checks the internal transmission harness and solenoid "B".


Diagnostic Aids:
Check all connections, especially those at the transmission pass-thru connector.