Six Tips for D-C 41-Series Automatics

1. Code 14 — ETAX relay always on

This one occurs when the trans controller checks pin 16 and 17 for voltage corresponding to open points on the relay. (greater than 3 volts) Relay locations are on the controller body, passenger’s side fender well, or fuse box. The primary cause is welded relay contacts, but there are others:

* Short to ground in SA1 circuit

* Open in SA1 circuit between relay and ground

* Open in SF1 circuit between relay and ground

* Open in J91 circuit from relay to ground

* Open in J11 circuit from relay to

* 60 pin connector problem (pins 15,16,17)

* Faulty controller

Quick Check: Swap the ETAX relay with the back up light relay.

Code 15, ETAX relay always off can be checked the same way.

2. Code 18 — Engine speed signal circuit

This code indicates that the trans controller is not receiving information it needs from the SBEC. Possible causes include:

* Open or short in N7 circuit — distributor pick up signal

* Bad sensor in distributor

* 60 pin connector problem (pin 45)

Quick Check: make sure the correct SBEC is installed in the vehicle. Some inexperienced techs swap boxes indiscriminately when diagnosing transmission and engine drivability issues.

3. Code 19 — CD2 bus communication

Like Code 18, the transmission controller is not receiving information it needs from the engine ECU. Possible causes include:

* Opens or shorts between pin 46 (engine controller) and pin 4 (transmission controller)

* Opens or shorts between pin 26 (engine controller) and 43 (transmission controller)

* Faulty engine controller

* Faulty transmission controller

4. Code 21 through 27 — Pressure Switch Circuits

21 – Overdrive

22 – 2/4

23 – 2/4 and Overdrive

24 – L/R

25 – L/R and Overdrive

26 – L/R and 2/4

27 – All Pressure Switches

Codes 21 through 27 occur when the controller checks the status of the pressure switches and finds that they’re open or closed at the wrong time. Possible causes include:

* Faulty seals at the solenoid block

* Loose female connector pins in the solenoid harness

* Opens/shorts

* Faulty controller

Loose connectors are a common problem. A simple method for testing the connection uses drill bits. Using a #43 bit (0.089″), insert into each hole in the connector. There should be a slight drag when inserted and removed. If the drill is loose in the connector, re-insert the drill and squeeze the connector down over it with a very small needle nose pliers or screwdriver blade.

For the open/shorts condition, use an ohmmeter (not a continuity tester) between the solenoid 8-pin connector and the controller’s big 60 pin connector. Test points are:

Solenoid pin 2 to controller pin 50 (Low/Rev)

Solenoid pin 1 to controller pin 57 (2/4)

Solenoid pin 1 to controller pin 9 (OD)

5. Code 29 — TPS signal

Code 29 occurs when the transmission controller sees the TPS signal as out of spec, or intermittent. If this one occurs as a comeback from a drivability service, or from another shop where engine work was performed, the fix may be very simple. The previous tech may have cleared the SBEC code from the faulty TPS, but forgot to tell the transmission computer. If after clearing the code it recurs, check the TPS from the underhood diagnostic connector. If the TPS checks good from the engine’s perspective, then the engine and transmission controllers have an open or short in their connecting wiring.

6. Code 36 accompanied by any codes 50 through 55 — Fault immediately after shift

Codes 50 through 55 are speed error codes for each ratio as measured by excessive changes in turbine or output shaft speeds. If present with a code 36, possible causes are:

* UD/OD snap ring broken

* Burnt OD clutch pack

* Gearset failure

This combination of codes is a sign of terminal trouble inside the case, calling for ‘re and re’. Speed sensor connectors can cause intermittent 50 series codes, and an improved conector assembly is available from DaimlerChrysler, but the combination of the 36 and 50 series strongly suggests mechanical damage. Talk to your rebuilder and try to let the customer down easy.