How do I search for PZM B2471 ?

[TDK]

Dear all,

Our 99' Deville still has an occaisonal "whirr" from the left-engine area if set into Drive at too high an RPM or if the gas is touched too hard from a start. I let off the gas, it quiets and drives out just fine. There are no other symtoms at any other hard throttle or speed. This is the same issue I noted in this forum - that started last fall after a minor tire-spin and stop at a gas station icy speed bump. It may becoming more "sensitive".

There are no immediate messages or codes during the "whirr" nor are there any current codes immediately afterwards. This PZM B2471 showed up in history today, (it would be really handy - if they were time/date stamped...). There was also a TCS-1225 some time ago as I recall, but it was history and has not re-appeared.

Obviously, the concern is that the tranny is going out for whatever reason (odd with only 45,000-miles). My hope is that the traction control is somehow "over-active", such that its application is the noise I hear at times, (seems familar, but there are no "Traction Active" messages during the whirr). Perhaps the engine RPM is too high for the apparent ground speed?

And, of course, we are about 980-miles from home at this time...

Thanks in advance,

[JimD]

B2471 - Interior Lamp Fault

This one will not ruin your trip.

C1225 - Left Front Excessive Wheel Speed Variation

This one could be related to the ABS applications you are hearing.

[Cadillac Jim]

B2471 Interior Lamp Fault

Find the bulb and change it.

The buzz is your traction control system (TCS) spinning up its motor to apply a front brake to stop tire spin. It didn't start when you invoked it on ice, it's normal. You won't get a message on the DIC if the TCS is on for less than about a second (I'd have to search the FSM to get the ON time to DIC display, and that would be definitive only for the 1997 model year).

If it's happening too often, check these things:

• Make sure that your front tires are the same brand and type, and that they have the same amount of wear. Front tires on a FWD car should always be changed or rotated in matched pairs.
• Make sure that the inflation on the front tires is matched.
• If you can jack up the front of the car, make sure that both wheels turn freely, and that the wheel bearings and suspension are tight.
• Check the connectors to the wheel speed sensors (on the hub centerline on the inside) are clean and tight.

Write down all your OBD codes and post them here. Don't forget to include whether they are Current or History.

[TDK]

JimD and Jim's 97 ETC,

Thanks for the advice. We were out to Boulder, CO with our new grandson for a few hours, (why I did not reply sooner).

I also managed to find the following tidbit on a Google search, (from "the other site..."):

"This may help anyone who hears a buzzing noise from a dead stop and the traction control engages, setting a tcs1225 code. My 1997 sls had this problem occur. There appears to be a problem from the factory in the wiring harness that the wires run through for the left front abs/traction control to the EBTCM, which on my year is mounted on the left front frame rail close to the radiator. These wires send the signal from the EBTCM to the left front wheel.

After doing some research, GM had a bulletin and a repair "kit" to solve this particular issue.

The GM part # 12167672 is called the left front wheel speed harness by-pass repair kit.

You do not have to remove the wheel to perform this operation.

The instructions are pretty straight forward, and it will take about 3/4 hour.

You will need to remove the factory air cleaner box and the radiator hose, which they don't tell you to do, and make sure you have plenty of light since you are removing 2 very small connectors and replacing them with the new ones. You will also need a diagram ( EBTCM Connector C1 and C2) which will show you which wires to replace. (which also is not supplied)."

Gentlemen; thanks again on the TCS-1225, this "advice gift" really eases my mind.

Now, finding and wriggling around to fix whatever interior light bulb may be another matter...

[JimD]

I would be reluctant to apply Seville wiring fixes to a Deville model.

[TDK]

Dear All,

A friendly tone let me know that a C-1284 code - Lateral Accelerometer Sensor Bias Malfunction was set. This appeared about an hour from home while at about 83mph straight and level. There were no other indications of anything amiss, the cruise stayed on at 83 and there was no ABS pump activation etc. The C-1225 code has not reappeared, but the pesky B2471 - Interior Lamp Fault is history again (and all appears to be lit...). There are no other codes current or history.

This latest C-1284 may have something to do with the EBTCM or the cable(s) connection etc, (since the car was not really in a full drift or at several G's...). However, the initial C-1225 Left Front Excessive Wheel Speed Variation, appeared immediatley after a slight wheelspin and brake. So I think something mechanical/electrical came loose or a electronic parameter reset itself to an incorrect baseline, (not just a flaky EBTCM).

Maybe a long-term battery disconnect might correct a faulty data point?

I crawled underneath but have not yet figured out how to get to the speed-sensor cables at the left front wheel. It seems like the connections may be under the air cleaner box.

Both front tires are identical mfg/type and inflated the same as well with perhaps 10,000-miles on them.

In general; the car was full LOF serviced prior to the trip and the tranny fluid was drained and refilled with new, (not flushed).

I will probably take it to the GM dealer this comming week. They are OK and all, but they could not get it to mis-behave last fall. Now it is easy to engage the ABS pump with anything but "feathering" off the line.

Incidently, The BRD (Big White Dog), delivered 25.0 mpg over the 1,912-mile trip at an average of 63.9 mph, (a lot of Denver traffic to/from Lowes [Mr. fix it stuff] in there). It seems the traffic on I-80 and I-7- is a bit slower lately. I also backed off a bit to around 81-83 mph cruise. Only one Trooper flashed his lights - but these Caddies are respectable. With seat belts on and genuflecting every now and then - they just roll on - where "flashies" get pulled over for a chit chat.

Thanks,