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Home >> Ford >> 1990 >> Bronco II 4WD, Standard, M5OD-R1 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Test Tb - A4LD Transmission >> Test Tb: Step 1
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Test Tb: Step 1

1) Code 86 or 89: Check Solenoid Resistance  Code 86 indicates ECA did not see a voltage drop when the Shift Solenoid (SS) was activated. Code 89 indicates ECA did not see a voltage drop when the CCO solenoid was activated. Possible causes for this fault are:

Verify codes match appropriate transmission solenoid circuit.

TRANSMISSION SOLENOID CIRCUITS

Solenoid ECA Signal Output Pin KOEO Code
Converter Clutch Override (CCO) 53 89
Shift Solenoid (SS) 3/4-4/3 52 86

Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pins No. 37 and 57 and ECA signal output pin at the breakout box. If the resistance is 26 to 40 ohms, go to step 4). If resistance is not 26-40 ohms, go to next step.