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Hello all. I have a new problem with my 1997 XJ6. It has about 140,000 miles on it and, yesterday the transmission dash light came on. I had recently replaced an O2 sensor and it drove fine for about 100 miles and, in fact, it still seems to drive fine, but the light is on and it makes me nervous.
I checked the fluid hot and it was low. I added about 3/4 of a quart to get it in the correct range but the light is still on.
Any ideas?
On the left side of the car at the transmission area there’s a brown connector. Pull it back and twist the locking tab, clean out any corrosion in there.
HI Xalty. Thanks again for the quick response. Should I be able to see this connector from the top? I saw a tan connector as you can see in the pic. Thanks again for your help.
HI Xalty. Thanks again for the quick response. Should I be able to see this connector from the top? I saw a tan connector as you can see in the pic. Thanks again for your help.
Left as in US driver’s side. It’s only visible from under the car, located close to the transmission pan. If you have long arms and small hands you can pull it out without jacking the car up.
Hi Motorcarman. I used my OBDII scanner and it has no codes.
Thanks,
Dan
The ECM will NOT log all the TCM DTCs.
Many times the TCM will indicate to the ECM that a DTC is logged in the TCM so that you can be aware that the TCM is 'crying-out' for attention.
A generic OBDII ECM reader will NOT always (if ever) access the TCM.
You are ONLY communicating with the ECM. Try communicating with the TCM for a more complete picture.
Attached is the ZF 4HP24 DTC Summaries manual, which will give you an idea of the malfunctions that can trigger the transmission warning lamp.
A couple of issues I can think of that can trigger the transmission warning lamp but no transmission code include low battery voltage (especially while cranking the engine). Also, a problem with the Throttle Position Sensor (TPS) or a dirty Mass Air Flow Sensor (MAFS). Both the ECM and TCM rely on the signals from the TPS and MAFS to orchestrate smooth gearshifts. Also referenced is the Crankshaft Position Sensor (CKPS), but since your engine is running, that is probably not your issue.
I agree with xalty's advice to clean the electrical connector at the transmission, which can become contaminated with transmission fluid/oil.
Also, it is worth cleaning the ground points referenced by the ECM and TCM. You can find these in the Electrical Guide, which you can download at this link:
One thing to bear in mind is that the on-board diagnostics system on the X300 is very primitive. 1996 was the very first year for the OBDII standard in the U.S., so the system does not always provide as much information as we would like.
It would be worth checking your fluid again if you did not follow this procedure, because it may still be low. With the transmission fluid hot from a good drive of at least 15-20 minutes, park on a level surface. Press the brake pedal and move the gear selector lever through all positions, holding it in each position for at least 3 seconds (PRND32). Put the lever back in Park, then check the fluid level. You want it exactly at the max hot line. Add small amounts and recheck until it is exactly at that line. You added 3/4 of a quart already, which is a very significant shortage. Even a pint low can cause problems. Overfilling can also cause problems.
One other issue is to be sure you use a fluid that conforms to the original Dexron III specification. Many modern fluids are significantly thinner (of lower viscosity) than Dex III, even though their manufacturers claim they are backward compatible with Dex III. The most commonly-available fluid I know of with the correct viscosity is Valvoline Dex/Merc in the blue bottle (not the synthetic version in the red bottle, which is much too thin). The best fluid I know of is Redline Oil D4 ATF, and Mobil 1 ATF is also good (both are synthetic fluids but have viscosity indices in the correct range), but I would recommend those for a complete fluid change rather than a top-up.
The fact that you had to add 3/4 quart indicates that you have a leak, so it would be prudent to identify and resolve it.
Thanks Don and Motorcarman. When my wife got home from work, the light had gone out. Is it possible it takes a while to respond to filling? I did follow the procedure you mentioned and did fill to the top of the full mark.
I tried to get a picture of the left side of the transmission. Is the connector you mentioned visible?
Thanks again.
Sorry for the delay in responding. Yes, that's the transmission electrical connector. To disconnect it, rotate the outer collar counter-clockwise (as viewed from the rear of the vehicle) and pull the harness connector off of the transmission connector. It helps give you more slack if you remove the screw securing the harness clip that is visible in the upper right corner of your photo.
Jag-Lovers still hasn't transferred all of the large images to their new servers, but here are some instructions:
X300 gear box (transmission) light
