WTF another Code?

Danno · **Posted:** Sat Nov 11, 2006 5:23 pm

Anyone have any clue what exactly a P0504 code means? So far only thing I noticed is that cruise control isnt working.

P0504 Brake Switch "A"/"B" Correlation

spoonplugger1 · **Posted:** Sat Nov 11, 2006 5:37 pm

They put an announcement sticky near the top of the page with all the codes and you can't use it?

Danno · **Posted:** Sat Nov 11, 2006 5:57 pm

spoonplugger1 wrote:

They put an announcement sticky near the top of the page with all the codes and you can't use it?

Ahhh, Yea I can use it, if you noticed I posted the exact DTC from the sticky. As we all know the OBDII Codes are not all that clear as to what the problem exactly is. I posted so I can find out if anybody out there can explain in more detail or, if anybody has had it also. Jeep dealer doesnt know what it means.

MrMopar64 · **Posted:** Sat Nov 11, 2006 7:10 pm

There are two "switches" inside of the actual switch on the vehicle - it's a redundant system, as is the accel pedal sensor (there are two "sensors" in there for redundancy - safety). The engine's ECU checks for plausibility between the two switches - if both aren't working, some functions will be disabled (like cruise).

You most likely need a new switch, or there is a wiring problem. I'd bet on the switch.

RFCRD · **Posted:** Sat Nov 11, 2006 7:34 pm

There is also a reference to brake switch problems noted in several ECM reflash TSB's. You may want to start by getting the latest software TSB 18-023-06 done, see if it goes away.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Quote:

The engine's ECU checks for plausibility

Speaking of the engine ECU, a couple of us who have had the latest flash performed noticed a power decrease. On mine, it was flashed when they replaced the 2nd egr valve. Are you aware of any detuning to the latest ECU software to prevent further torque converter/tranny problems?

RFCRD · **Posted:** Sat Nov 11, 2006 7:51 pm

Ranger1 wrote:

Quote:

The engine's ECU checks for plausibility

Speaking of the engine ECU, a couple of us who have had the latest flash performed noticed a power decrease. On mine, it was flashed when they replaced the 2nd egr valve. Are you aware of any detuning to the latest ECU software to prevent further torque converter/tranny problems?

Got mine back on Wednesday from my regular healing service. They replaced the TCM (again, on #6 now) including the latest software. Runs out fine but I did notice it's not as peppy but think it in the shift logic. Find myself using the "OD-off" button to get a passing gear where I didn't need to before the reflash.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Mine runs fine as far as the engine goes, but there is definitely less power than before. It almost seems like a limiter is on the engine. I recall that the European 2.8L CRD's had a lower power programming for a year before the USA spec model came out. It was rated at something like 154hp and 266 ft-lbs of torque, so we know the ECU software is out there for lower power levels if DC wanted to use it. Different emissions map I'm sure, but it would not surprise me if they lowered the torque/hp to stretch the TC/tranny life somewhat. The power loss on mine is such that it does not have the low down grunt torque it used to - I too have to use the overdrive button to pass now - never had to use it before at any time.

MrMopar64 · **Posted:** Sat Nov 11, 2006 8:17 pm

With regard to the engine controller, no changes have been made recently to engine output. The original release @ beginning of '05 would've been 360 ft-lb, now is around 300. All '06 have been same output level.

However, my guess would be there has been a change in the TCM software that is causing most of it. The TCM has the ability to request a decrease in torque in certain situations and my suspicion is that the decrease is coming from that.

ECM software can be tailed to make output whatever is desired - that's the beauty of calibration. However, as I'm sure you've all seen, a balance between reliability and power has to be reached - and when using components such as the 545, reliability is a definite issue.

If anyone is in Europe in the spring when the 2.8 CRD KA (Nitro) is released, take it for a spin. The W5A580 transmission is an amazing unit, and the NVG370 six-speed is an incredible amount of fun.

RFCRD · **Posted:** Sat Nov 11, 2006 8:24 pm

Ranger1 wrote:

Mine runs fine as far as the engine goes, but there is definitely less power than before. It almost seems like a limiter is on the engine. I recall that the European 2.8L CRD's had a lower power programming for a year before the USA spec model came out. It was rated at something like 154hp and 266 ft-lbs of torque, so we know the ECU software is out there for lower power levels if DC wanted to use it. Different emissions map I'm sure, but it would not surprise me if they lowered the torque/hp to stretch the TC/tranny life somewhat. The power loss on mine is such that it does not have the low down grunt torque it used to - I too have to use the overdrive button to pass now - never had to use it before at any time.

Would think there is some type of legality to cutting back power. They represented a 160hp/290ft-lb package when they sold this, would think DC could get in a pile of legal trouble over this if they tried and would be openly admitting they had and engineering problem. Of course, they also represented a reliable/working product too which they havent quite lived up to that expectation.

On the F31 recall work done to mine, don't know if they actually fixed the data link problem. They were unable to reflash the TCM so the installed a new one and tried again which again failed to communicate. They finally installed another new TCM with the software pre-loaded. Same problem happened with TSB 18-009-06. Tempted to stop at the local E-check station, see if they can test it.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Quote:

Would think there is some type of legality to cutting back power.

Possibly, but it may have been a temporary fix until they find the problem with the tc/tranny failure. Once that's done, another flash de jour and we're back to normal, no one the wiser :-)

RFCRD · **Posted:** Sat Nov 11, 2006 8:37 pm

Ranger1 wrote:

Quote:

Would think there is some type of legality to cutting back power.

Possibly, but it may have been a temporary fix until they find the problem with the tc/tranny failure. Once that's done, another flash de jour and we're back to normal, no one the wiser :-)

True, Isn't everything a temporary fix with this beast?? It's really sad, I could have put my $25K into a new Silverado a year ago and not met all these nice folks on-line.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

MrMopar64 wrote:

With regard to the engine controller, no changes have been made recently to engine output. The original release @ beginning of '05 would've been 360 ft-lb, now is around 300. All '06 have been same output level.

However, my guess would be there has been a change in the TCM software that is causing most of it. The TCM has the ability to request a decrease in torque in certain situations and my suspicion is that the decrease is coming from that.

ECM software can be tailed to make output whatever is desired - that's the beauty of calibration. However, as I'm sure you've all seen, a balance between reliability and power has to be reached - and when using components such as the 545, reliability is a definite issue.

If anyone is in Europe in the spring when the 2.8 CRD KA (Nitro) is released, take it for a spin. The W5A580 transmission is an amazing unit, and the NVG370 six-speed is an incredible amount of fun.

Thanks for the info... mine was built March 1 2005 so it had one of the first releases of software. I miss the early grunt!!! If DC is using the WA580 on the 2.8L CRD KA in Europe, it says a lot about the future of the 545 in any more diesel powered vehicles. I'm still puzzled how this tranny could handle the Hemi V8, but not the CRD so easily.

Danno · **Posted:** Sun Nov 12, 2006 12:16 am

Thanks for the Explanation. I called the jeep dealer again and they said most likely it was a fluke. I cleared the code out, and cruise is working again. I did make an appt for them to take a look at that just in case. As well as having them find that darn oil leak, they put some die in it this time so they could see it better.

WTF another Code?

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