Test Tb - A4LD Transmission

Perform this test only when Code 86 or 89 is displayed or referred here by other chart or test procedure. To prevent replacement of good components be aware that the following non-EEC areas may be at fault:

Hydraulic or emergency brake system
Transmission linkage
Internal transmission components

This test is intended to diagnose only the following components or circuits:

Harness circuits (CCO, SS 3/4-4/3, VPWR)
CCO solenoid

Shift solenoid 3/4-4/3

Fig 1: A4LD Transmission Circuits

TEST PIN NO. 53 WIRE COLOR IDENTIFICATION

Application	Wire Color
2.3L OHC	Orange/Yellow

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:

CCO/SS resistance out of limits
CCO/SS circuit open or grounded
Faulty ECA

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.

2) Check Continuity of Vehicle Harness Circuits - With key off, install breakout box. Leave ECA and transmission bulkhead connector (A4LD solenoids) disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pins No. 37 and 57 at the breakout box and VPWR circuit pin of the vehicle harness connector at the transmission. Measure resistance between the appropriate ECA signal output pin (No. 52 or 53) at the breakout box and same circuit at the transmission vehicle harness connector.
3) Check Transmission Vehicle Harness Circuits - With key off, install breakout box, leaving ECA disconnected. Disconnect transmission bulkhead connector. Set DVOM on 200-k/ohm scale. Measure resistance between the appropriate ECA signal output pin and test pins No. 37 and 57 at the breakout box. Measure resistance between the appropriate ECA signal output pin and test pins No. 40, 60 and 46 at the breakout box and at chassis ground. If all resistances are greater than 10 k/ohms, go to next step. If any resistance is less than 10 k/ohms, repair short circuit. Remove breakout box and reconnect components. Rerun QUICK TEST.
4) Check VPWR Voltage to Transmission Solenoids - With key off, breakout box installed and ECA connected, set DVOM on 20-volt scale. Disconnect transmission bulkhead connector. Turn key on, leaving engine off. Measure voltage between test pins No. 37 and 57 at the bulkhead connector and chassis ground. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, replace ECA. Remove breakout box and reconnect all components. Rerun QUICK TEST.
5) Check Output Driver Signal - Turn key off. Install breakout box, leaving ECA connected. Disconnect A4LD transmission bulkhead connector. Connect a test light between test pin No. 37 or 57 and appropriate signal output pin at the breakout box. Enter KOEO Self-Test. If test light flashes momentarily and then stays off, fault is internal in transmission. Repair internal electrical fault as necessary. If light does not flash momentarily and then stay off, replace ECA. Remove breakout box and reconnect all components. Repeat QUICK TEST.