GENERAL INFORMATION

The information in this manual is designed to help the technician understand and repair the transaxle with the aid of the built in on-board diagnostics.

Chrysler Corporation has developed a complete set of diagnostic manuals which cover the diagnosis of this transaxle. They have been designed to make transaxle diagnosis accurate and simple. Use these manuals with the DRB II and the latest cartridge, when diagnosing transaxle problems.

ON-BOARD DIAGNOSTICS INFORMATION

The transaxle is controlled and monitored by the Electronic Automatic Transaxle (EATX) controller. The controller monitors critical input and output circuits within the transaxle.

CAUTION: A 1992 EATX Controller will not interchange with any previous model year controllers. Use of a previous year controller on a 1992 vehicle will cause transaxle performance problems.

Some circuits are tested continuously; others are checked only under certain conditions. Each circuit monitored by the EATX controller has a corresponding fault message assigned to it that can be read with the DRB II.

If the on-board diagnostic system senses that one of the circuits is malfunctioning, the corresponding fault message is stored in memory. If the malfunction goes away after the fault code is stored, the controller will erase the fault after 75 key cycles.

CCD BUS

In order to diagnose the EATX, fault codes in the EATX controller's memory should be read using the Diagnostic Readout Box (DRB II). If more than one fault code exists, diagnostic priority should be given to the most recent code. With CCD bus bias and communication problems, however, the DRBII displays an appropriate message and fault codes might not be accessible until the bus problem is fixed. The following is a list of probable causes for a bus problem:

² Open or short to ground/battery in either or both CCD bus wires (pins 4 and 43).

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Limp-In Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

On-Board Diagnostics Information . . . . . . . . . . . . 143

System Fault Messages/Codes . . . . . . . . . . . . . . 143

²Open or short to ground/battery in either or both EATX bias wires (pin 5 and 44) on vehicles requiring EATX to bias the bus.

²Open or short to ground/battery in the diagnostic connector bus wire.

²Internal failure of any controller connected to the bus.

The CCD bus should have 2.5 volts (+2.5 volts on CCD+ and -2.5 volts on CCD-).

The bus error message displayed by the DRB II should be helpful in diagnosing the CCD bus.

For more information on diagnosing CCD bus problems, refer to the 1992 Diagnostic Procedures Manual for non-communication with the CCD bus problems. All other problems refer to the 1992 Body Vehicle Communications Diagnostic Procedures Manual.

SYSTEM FAULT MESSAGES/CODES

Fault codes are two-digit numbers that identify which circuit is malfunctioning. A fault code can be set for hydraulic and mechanical reasons as well as for electrical problems. In most cases, fault codes do not pinpoint which specific component is defective.

Fault code can only be read with the use of the DRBII Read-out Box or equivalent.

HARD FAULTS

Any fault code that comes back within 3 engine starts (reset count 3 or less) is a ``Hard Fault''. This means that the defect is there every time the controller checks that circuit.

SOFT FAULTS

A ``Soft Fault'' is one that occurs intermittently. It is not there every time the controller checks the circuit. Most soft faults are caused by wiring or connector problems. Intermittent defects must be looked for under the specific conditions that caused them.

LIMP-IN MODE

The EATX controller continuously checks for electrical and internal transaxle problems. When a problem is sensed, the controller stores a fault code. All but twelve of these codes cause the transaxle to go into the ``Limp-in mode''. While in this mode, electri-