Community Forums

Full-Timers · 01-31-2010, 08:22 PM

OK, here is my take on this whole subject. If the Engine light came on and it went into “Limp Mode”, or even if it did not go into “Limp Mode”, THERE WAS A PROBLEM detected. It was not just nothing. It may have been a glitch or it may be a marginal situation indicating a more major failure is coming. But in any case it should not be ignored. If the light was on there most likely is a code stored and your local auto parts store can read it for free and let you know what it was. At that point you can decide weather to ignore it or not. If it were up to me, I would want to know.

Now as far as the “Limp Mode”, we really don’t know what “Limp mode” is. Does it simply limit your RPMs to 3000…I doubt it. I have a feeling it does a lot more like for instance disable some sensors, set engine modes to a default setting, and more to protect your engine and at the least GET YOU HOME or OUT OF DANGER. I would much rather have the “Limp Mode” then be dead on the road in a bad situation.

DriVer · 01-31-2010, 08:56 PM

Quote:

Originally Posted by Full-Timers

I would much rather have the “Limp Mode” then be dead on the road in a bad situation.

I think that just about sums up my previous thesis.

CoastieSCPO · 01-31-2010, 09:43 PM

Dieselclacker;

That's what happened. The light went on, we had to drive at reduced power and the authorized WH service center said that it was the plug. Now, I will admit that maybe I'm calling it limp mode or reduced engine power mode, when it really wasn't. But that is what I believed it to be. That is a possibility and the engine was running on only 7 cylinders causing what appeared to be limp mode.

Bob

DriVer · 01-31-2010, 10:13 PM

Quote:

Originally Posted by CoastieSCPO

That is a possibility and the engine was running on only 7 cylinders causing what appeared to be limp mode.

Chief, I just went through that drill and I wasn't in either mode. I was backfiring on power application and had a very bad miss and a slight loss of power until I disconnected and reconnected my battery cable in a rest stop. Once we got going again, I had a miss but no SES, DTC or limp home function evident. The condition improved to the point where it didn't backfire any further and I ran the balance of our trip about 150 miles or so until we got home.

Brazel's RV Performance · 01-31-2010, 10:45 PM

I've seen quite a few and if you go on the diesel forums you will also see that Chevy Duramax's can be pushed into limp mode fairly easily...especially with power upgrades. It's not an "unheard" of event, especially with all the technology built into these vehicles now, and I agree that sometimes simpler is better

To the OP...the most common issue we find that puts them into limp mode is an issue with the TAC Module (Throttle Actuator Module). I'd be curious to know if the code is related to that or not.

"007" · 02-01-2010, 02:23 AM

I use to put my coach into limp mode by adjusting the CC speed with CC switch and quickly releasing switch.

I now adjust speed with gas pedal and pushing button on end of gear shift.
To many times going into limp mode in heavy traffic.

Rich Pratt · 02-01-2010, 07:19 AM

WOW! I wish I could have motivated my former students to be so passionate,articulate and helpful in their writings and daily living. I have an appointment tomorrow at a facility that has a Tech II. Thanks and I'll let you know the results.

DriVer · 02-01-2010, 07:55 AM

Quote:

Originally Posted by Rich Pratt

WOW! I wish I could have motivated my former students to be so passionate,articulate and helpful in their writings and daily living. I have an appointment tomorrow at a facility that has a Tech II. Thanks and I'll let you know the results.

A Community is a beehive of information sharing and we would hope that the message is upbeat and progressive but that is not always possible because some folks have had disappointments. What motivates "most" of the members here is to be helpful in sharing their experiences. We are looking forward to hearing the results of your T2 scan!

wa8yxm · 02-01-2010, 08:29 AM

If you visit an auto parts store such as Advance Auto, Auto Zone, Discount Auto, Sears, NAPA or,, Well it's a long list, you can get an OBDII code reader.. This device plugs into a socket normally located along side the steering collumn and it will give you, Depending on how much you spend on it, either a serries of numbers (Write them down) or their translations. This tells you why the computer reduced engine power.

It may or may not help fix it

My car, is OBD 1,,, Recently I had engine problems

I read the codes, and found 3 of 'em (OBD-1 readers are kind of low Cost.. I used a paper clip to read them)

First code was 12 (No pulses from ignitin module) Normal since the engine was NOT running

Second code translated to "Low voltage Fuel Pump" Well, we had run the battery down

Third code was the winner: Oxygen Sensor, Excessively Rich fuel mix.

Now we had fixed that. but it took a while to get the engine hot enough to burn the sensor clean.. It runs fine now.

In an eariler failue my OBD-1 engine told me "MAP Sensor Problem" I popped the hood, MAP sensor is quite literally the 1st thign you see on my car (It is on the front of the air cleaner housing, It has some wires hooked to it (They were) and a hose that runs back to the manafold.. Or rather it is supposed to run back toward the manafold.

I re-connected the hose..and VAROOM, all was good again.

Rich Pratt · 02-02-2010, 04:36 PM

Today I took the coach to a local RV dealer. The tech used a Tech II and found that the MAP sensor needs replacement. The module is ordered, so we'll see in a couple of days. Interestingly, the check engine light went out, but there is a problem that the T2 picked up.

DriVer · 02-02-2010, 06:23 PM

Quote:

Originally Posted by Rich Pratt

Today I took the coach to a local RV dealer. The tech used a Tech II and found that the MAP sensor needs replacement.

OK, Good luck with the repair and it's funny how those darned lights will go off. I'm just wondering now if the T2 would be able to duplicate the EC it picked up the first time now that the SES light went out.

The tech probably cleared the code and perhaps this is what reset the SES lamp.

"007" · 02-02-2010, 06:59 PM

I have found after causing engine, with CC switch slip, light come on, 3 or 4 restarts ECM would reset and engine light would go out.
Did the tech clean the MAP sensor or unplug it. If you do not now have light after restart of engine I would hold off buying a new MAP.

Rich Pratt · 02-07-2010, 02:41 PM

Just wondering how much everyone thinks the replacement of the MAP sensor should be. I'm scheduled for replacement Tuesday. We're not in a rush as we're settled until mid March, so I waited for an opening to also get service and a couple of minor other things done. Awaiting your replies and thanks

JCM · 02-07-2010, 03:57 PM

I have had the "reduced engine power" 2 times after hitting the cruse control button and hitting a bump at the same time. Diagnosed the first time as a loss of communication with the throttle sensor and the engine computer. I cleared the error code the second time with my Interceptor Scan Gauge.
I wonder why it never went in to limp mode when the oil pump shaft extension sheared and the oil pressure dropped to 0. I would of thought that would be another “critical” function. Oh well the warning came on the bottom of the Speedo and the alarm sounded off. The Interceptor Scan Gauge saved my but by showing oil pressure fluctuating, then going to 0. Thank goodness the engine was fine. Wh rep said many went onto self destruction because the operator didn’t hear the alarm or didn’t see the warning. Again a reduced power function may have saved a few engines.