Where is Tran Control Module, Airbag module (2001 Ram) ????

I want to unplug the TCM and the airbag module from the wiring/control bus. 2001 RAM, 2WD, short cab, 318 (5.2L) with upgraded interior.

There is a small plastic cover on the tranny hump under the dashboard held with 2 screws. I take that off and there's a big connector right there attached to something. Is that the airbag controller? If so, then where's the tranny controller?

The HVAC cluster also has about 2 or 3 connectors (which I unplugged).

I unplugged 2 connectors on the brake unit (I take it this is the ABS controller).

I unplugged the 3 cables going to the PCM.

I unplugged the DRL module.

I STILL GET NO BUS MESSAGE, and CCD message on the overhead console.

Where the hell else is this bus going to ?!?!?!

Does anyone know which pins on the 2 cluster connectors is this bus?

Is it 2 wires, or one?

Does it go to the ODB connector?

Reply to
MoPar Man
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You really don't know what you are doing and could be causing more problems for the person that is going to end up working on it after you soldered and disconnected things. As I said before if you have a total bus loss it may be caused by the PCM which would be covered under the 8/80 warranty. Why not take it to the shop and explain to them what you have done so they can fix it. The BUS is a set of wires that all the computers communicate with. If a module is shorted out it could cause all the modules to lose communication with each other. If you have a connector that is loose or a wire that is pulled out as I stated before that could also cause a bus failure. You would have to use a volt meter to measure the bus voltage on each module to see where the problem is or have a scan tool connected as you disconnect each module one at a time until you locate the problem. If you probe a wrong wire with a volt meter and it happens to be an air bag/air module wire you could deploy the air bags possibly causing injury to you or the vehicle.

Sorry no help here.

Glenn Beasley Chrysler Tech

Reply to
maxpower

I called the service dept at a Dodge dealership and described the problem. The guy said that something is messing up the data bus and the only way to diagnose it is to unplug the various modules on the bus.

He thinks it's probably the cluster itself -> but would that explain the CCD message on the overhead console? Or the fact that initially the engine would crank but wouldn't start?

Unless I'm wrong, CCD stands for "Chrysler Collision Detection" and is the data bus system used by the airbag and the anti-lock brake systems. Is the overhead console connected to those systems via the cluster, or around (bypassing) the cluster?

The glove-box owners manual says to check a smaller booklet for warrany information.

The smaller warranty booklet (2001 Canadian Warranties and roadside assistance) says that everything except tires is covered by a 3-year,

60,000 km warranty. If it has a diesel engine (which it does not) then some engine parts are covered by a 5 year, 160,000 km warranty.

Outer body panels are covered against corrosion for 5 years/160k. The booklet goes on to say that for cars and light-duty trucks, the "defect warranty" covers the following major emission-control parts for 8 years or 130,000 km: Catalytic convertor, Powertrain control module.

A small half-page flyer (Five Star Protection - 5/100 coverage for

2001 models - Powertrain components - roadside assistance) lists items that are covered after the initial 3/60 warranty ends. These items are many engine parts (no electronic parts), transmission (including TCM), front and/or rear drive parts, and roadside assistance.

So the short answer is that unless this is a PCM problem, it *may* be covered on the basis that the PCM might be defective from an emmission-control point of view, and the 8-year warranty for that aspect hasn't yet expired. But by all indications all other electronic parts or wiring problems are no longer covered (the 5-year point would have been reached this past March or April).

According to a Chrysler parts dept guy, a PCM costs $1050 (CDN) which is equivalent to around $850 - $900 USD.

You mentioned earlier to check connector C130. When looking at the circuit diagrams in the Haynes manual, I can't see anything labeled as C130. I can see a C129 and C133 (I think C133 is the big connector under the dash) and C131 (fender-mounted Daytime running lights module).

The manual is wrong in that it shows all guages and indicator lights as having direct connections to the two cluster connectors (C215 and C216) but other than the high-beam lamps, the general illumination lamps and maybe the seat-belt and parking-brake lamps, everything else is driven by the electronics on the cluster circuit board. The manual shows that C215 and C216 are 14 pin connectors, while in reality on my cluster they're 10 pin each.

I am getting 12 volts at those connectors, and also getting a lower voltage (10 and 11?) on a couple of other pins. Where can I get the real pin-out for the cluster connectors?

If the problem is in the air-bag control unit, then is that covered under any non-specified warranty?

Reply to
MoPar Man

Not to give you a hard time but you have no idea what is going on with that vehicle. you are totally lost and that Haynes book you are using is causing you more problems then anything. The best thing for you to do with that book is to use it for heat in the fireplace come winter time. The bus system is very complicated and for someone that is not the least bit familiar with it should not attempt to repair it. This is my last reply to this post. Im sorry

Glenn

Reply to
maxpower

Update:

After disconnecting every connector I could find, and turning the ignition to on after disconnecting each connector, the "No Bus" and "CCD" messages did not go away.

Still no-one will tell me where the TCM is, but I'll look under the truck for that next.

So I connected everything back and still got "no bus" and "CCD".

Ok, so if the problem is the cluster, then let's remove the cluster. Then turn the key to ignition. Nope. The overhead console is still displaying "CCD" even with no cluster plugged in. Truck starts and runs fine without the cluster too.

(I've also had the overhead unit unplugged and still got the no bus message on the cluster, so it doesn't seem that there's a problem with that unit).

Glenn -

If you can provide any help at all, please tell me what code P1687 is (in more detail than the following:

P1687 (P1687 Driver 5 Line 7)

Alternate descriptions: (?)

No Cluster BUS Message No J1850 messages received from the Mechanical Instrument Cluster (MIC) module

No MIC BUS Message No CCD/J1850 messages received from the Mechanical Instrument Cluster (MIC) module

No messages received from the Mechanical Instrument Cluster module

Reply to
MoPar Man

Yes, that's what it stands for - but 'collision' in this case has nothing to do with a vehicle impacting something... it's describing the method for dealing with contention on the bus. Just like ethernet uses collision detection, that doesn't mean the hubs and switches are slamming into each other. Just about every control module has a CCD bus connection - that's how everything talks to each other. The overhead console is on the CCD bus, which is where it gets it's information regarding fuel economy, odometer readings, etc.

Also - there is no separate transmission control module. All transmission control is performed by the PCM.

That's because the Haynes manual is just about worthless when it comes to the electrical system. If you really want to go at this yourself, buy a factory service manual. Sometimes you can find them on EBay, or you can always get one from

formatting link
C130 is the big 43-pin connector in the power distribution center. C134 is the even-bigger 74-pin connector in the lower driver's-side firewall - it's where the entire instrument panel wiring harness connects to, and passes through the firewall. You disconnect it by unbolting it from the passenger compartment side (it's got a bolt in the center of it).

Reply to
Tom Lawrence

P1687 No communication with the MIC (mechanical instrument cluster) and as I stated in my first reply You need to verify if this is a total bus failure, or just simply a component issue. For instance the gages can drop out if there is a bus failure, if the cluster itself lost power or ground, or if there is an internal cluster or pcm failure. Also the gages can drop out if the ccd bus is shorted.. All of the modules talk back and forth over the ccd bus. If anyone of the modules, connecters, or ccd (bus) wires get shorted to power, shorted to ground or shorted to each other, or internally (module), then the whole bus communication system will stop. In turn all modules/components that are dependant on receiving the necessary bus messages will not operate. For instance the GAGES and OVERHEAD need the information from the pcm. A loose ground for anyone of the module can also cause a corruption in the CCD bus. The MIC (mechanical Instrument Cluster) is what creates the bus voltage. The ccd bus voltage should 2.5 volts, you can use a dvom and check this at the data link connecter. If the MIC has failed there will be no bus communication between the modules. The ccd bus cannot cause a die-out condition. The "NO BUS" may appear in the odometer, and the truck may stall if the PCM is lost (locked up)

Ok do this, First check to see if you have 2.5volts at pin 3 Vt/br wire of the data link connector and pin 11 wt/bk at the data link connector (The data link connector is the connector that the Scan tool connects to under the dash by your knee) if you don't have 2.5 volts on both wires then using an ohm meter (Battery disconnected) remove the cluster and test for continuity from pin#3 of the data link connector to pin number 10 of the cluster connector VT/BR wire. Then check pin#11 of the data link connector to pin 9 of the cluster WT/BK of the cluster for continuity. if both of those wires are good and you still don't have 2.5 volts check for 12v at pin#6 of cluster.

Reply to
maxpower

For the brief time that the PCM was talking to the MIC, the 1687 code was the only code coming through. Tells me that the PCM was talking (has been talking) to everything else ok.

I think it's more like they _will_ drop out if there is a bus failure. All guage data seems to come from the PCM - no MIC guages are wired directly to any sensors or transducers.

Of the 17 pins spread between the 2 dashboard MIC connectors, I've metered 7 of them to ground. One comes from the battery directly (it's always hot), and 2 others are hot when the ignition is turned on. The MIC odo display comes on nice and strong, and so do the indicator lights and the background illumination. So basically I think the MIC is getting all the ground and power it needs.

If the PCM's bus driver was faulty, then the "no buS" message on the MIC should go away when I unplug the 3 connectors on the PCM - no?

When I unplug the MIC, the "CCD" message on the overhead display should go away - no?

From a physical point of view, is this bus a single common wire that makes a simultaneous connection to all modules, or is it daisy-chained into and out-of each module?

???

If all the modules spew data onto the bus, then theoretically they all "add voltage" to the bus. And - what's this about "bus voltage" ??? How can the state of bus functionality be measured by looking at the voltage of the bus? If it's digital data, then I'd need a scope to assess the health of the bus - not a volt meter - no?

Again, is the bus a single conductor (ie wire) using ground return - or is it an isolated twisted-pair?

Is it wired as a common conductor between all modules, or does it go into and out-of each module in daisy-chain manner?

Ok, I'll check that - but here's what I don't get.

If this "CCD" bus is so great that Chrysler had to call it the "Chrysler Collision detection bus", then what is that doing at the ODB scan port (isin't the ODB port supposed to be manufacturer-independant and use some other whacky and overly-complicated way to deliver data to the outside world?)

Reply to
MoPar Man

Ok you know more then me. I do this for a living at a Chrysler Dealer

then as I said more to the next step

You just dont get it do you????

Hmm you still dont undersatnd!!! I told you there are 2 wires with 2.5v. those are the 2 bus wires. one is a plus and the other a minus

And you still dont get it!!! And I dont have time to teach you this system.

Take your truck to the dealer and have them fix it. GOOD LUCK!!

Reply to
maxpower

Don't ya just hate it when you miss the bus?

beekeep

Reply to
beekeep

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