reduced power mode

send us the code so we can investigate further. this may need a pro to look at it however. There is a TSB on this maybe for yours vehicle, see if the fuel injector harness has rubbed through on back of alternator. If it has this may be your problem and best ix is to repair the wires and install new conduit. you will need to remove the electrical connectors in pic.

Also check these locations for chaffed wires these are known trouble spots, and can lead to the damage of control modules... Page 1 of 3 No Communication with Any Modules, Memory Seat May Not Recall, Multiple U-DTCs ... No Communication with Any Modules, Memory Seat May Not Recall, Multiple U-DTCs Set or Instrument Panel Cluster (IPC) Warning Indicators, Crank No Start (Inspect/Repair Affected Wiring Harness) TECHNICAL SERVICE BULLETIN Reference Number(s): 03-08-50-014A,  Date of Issue:   January 20, 2006 2003-2006 Cadillac Escalade, Escalade ESV, Escalade EXT; 2003-2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe; 2003-2006 GMC Sierra, Yukon, Yukon XL; with Front, Individual (Non-Bkt) Seat (RPO AN3) and/or Active Brake Control (Stabilitrak(R)) (RPO JL4) This bulletin is being revised to update the various conditions and add the 2004-2006 model years, additional diagnostic and warranty information. Please discard Corporate Bulletin Number 03-08-50-014 (Section 08 - Body & Accessories). Related Ref Number(s): 03-08-50-014A Affected Model(s): Supercedes: ARTICLE BEGINNING CONDITION Some customers may comment on any of the following conditions: Various IPC Warning indicators are coming on. "¢ Driver Information Center (DIC) displays "Unknown Driver". "¢ Memory seat may not recall. "¢ RKE fobs may be inoperative. "¢ Radio or HVAC may shut off. "¢ Engine cranks but will not start. "¢ Upon investigation, the Technician may find multiple U-DTCs set. 10/7/2010 Page 2 of 3 No Communication with Any Modules, Memory Seat May Not Recall, Multiple U-DTCs ... CAUSE Fig. 1: Possible Pinch/Chafe Location Courtesy of GENERAL MOTORS CORP. On RPO AN3 equipped vehicles, a chafed or pinched seat wiring harness under the driver seat may be a cause of this condition. Because of the routing, a portion of the seat wiring harness may rest on the inboard edge of the seat track or frame. Over time, the harness may be pinched or chafed because of the seat movement. Refer to the above illustration. The illustration shows the inverted position of the seat bottom. The arrow shows the primary location of the possible harness chafing/pinching. Also, on any of the above listed vehicles, the PCM wiring harness may be chafing against the precharge pump bracket (Refer to Document ID# 1252958) or the battery tray. CORRECTION On RPO AN3 vehicles, inspect the routing of the seat wiring harness. Reroute the seat wiring harness and attaching harness fastener (1) to the opposite side of the seat module bracket. Repair the harness as necessary. Refer to Wiring Repairs in the Wiring Systems sub-section of SI. The seat may have to be removed for ease of access and proper repair of the wiring harness. Inspect the routing of the PCM wiring harness at the precharge pump bracket and the battery tray. Repair the harness as necessary. Refer to Wiring Repairs in the Wiring Systems sub-section of SI. Page 3 of 3 No Communication with Any Modules, Memory Seat May Not Recall, Multiple U-DTCs ... If any of the above conditions still remain after this repair, refer to SI for further diagnostic information. WARRANTY INFORMATION For vehicles repaired under warranty, use: Warranty Information Labor OperationDescriptionLabor Time N9542 Wiring and/or Connector - Seat System and/or PCM - Repair 0.2-0.4 hr

hi merlin , thank you I just replaced the Ignition a suck job but done ,no change, dash still flashes also new code 0753 any suggestions im almost warn out

Did you check for chafed wires yet? You may need to open the conduit to see the wires inside looking for bare wires.

That is a problem with the controls for the throttle actuator in the "drive by wire" system. It's a pretty complicated diagnosis that will likely require a professional scan tool to diagnose correctly.

A couple of weeks ago my truck went into limp mode. 15 minute drive home and I parked it. Got in the next day to take it to a mechanic and it was fine. Drove fine for 2 weeks then happened again. When I put it in park the engine revs fine, only does the reduced engine crappola in drive. Took it to a mechanic, actually 2 today and they could not get a reading from the computer thing. They say they need to fix the computer then get a reading then fix the problem. Sounds like a lot of money I don't have. Ideas or advice?

if they have to fix the computer is it because they can't read it? a lot of these limp modes are shorts in trans wiring from trans to pcm. You need to see what code it is first. Maybe the mechanic shold do a freeze frame and check things like that to get an idea of what's happening or maybe that has been done.

they are getting no power to the reader and when they supply power they get no reading.

then they have to fix the connection or why it's not getting power to reader and won't read first then they can scan it and find out why it's in limp mode.

I was afraid of that. 2 repair bills in 1 oh joy. Thank you for your help though.

tmay only be one to fix it and scan it

how do i get the truck out of limp mode??

You can disconnect the battery to reset the pcm, but you need to find out why its going into limp mode. Any trouble codes?

Computer problem
2004 Chevy Silverado V8 Automatic 195,00 miles

While driving, slow, fast, rough roads, interstates, cold engine, hot engine, the truck slows and an indicator reading states. reduced engine power. Could you tell me what the problem could be. If I turn off the truck for ten seconds or more it runs fine then does it again.

There is a fault within the electronic throttle, or possibly traction control. The slowing is a limp-home mode. This type of fault will have fault codes associated with it. As far as what it could be, the possibilities are many. If you can obtain the fault codes, it could narrow it down. A code reader, or scan tool is necessary.

I have a 2003 Silverado with the 4.8 engine with 63,000 miles. Since I purchased truck in March 2010, I have been getting a 'Reduced Engine Power" message and have to pull over and restart. I pulled code last night and got a P1518 (intake manifold runner control valve fault stuck open) any suggestions?

I don't know where you got that definition from but it doesn't apply to your vehicle. The definition on yours is ... "Throttle Actuator Control Module serial data circuit"
Your truck has a "drive by wire" system with all electronic throttle controls and there is a problem with communication in the system. This is not going to be a DIY type job as it will require some special equipment to diagnose it properly.

check to see if your battery is any good as well as your grounds. that is one of the things that will set this off. As you have a 2003 and its 'the original battery it's on borrowed time. But also make sure your charging system is up to snuff as well. that is your lTAC module that is givin g you troble or throttle actuator control module.

You're welcome. Let me know what you find.

Joe

I replaced both catalytic converters with bosal brand converters for my vehicle and also all oxygen sensors but the reduced engine power will not go away. Everything is bolted on and clamped.i even erased the problem with an ACTron OBDII reader. Am I missing something?

Why do you think it is the converters and O2 sensors? Unless the converters are plugged they normally will not effect engine power. The O2 sensors very seldom cause reduced power output either. What were the exact codes you had, and what were/are the symptoms?

I had 420 one of them and 7 others. The screen on the right side converter has collapsed.

Let check the rest again.

Here are my remaining symptoms after replacing converters. P0120, P0220, P1516, P2135, P0220.

P0120 - Throttle/Pedal Position Sensor 'A' Circuit Malfunction
P0220 - Throttle/Pedal Position Sensor 'B' Circuit Malfunction
P1516 - TAC Module, Throttle Actuator Position Performance
P2135 - Throttle/Pedal Position Sensor A/B Voltage Correlation

The P1516 and P2135 are the causes of the reduced power. But all four of these codes deal with the throttle body and gas pedal sensor circuits.

There are a few TSBs on these that basically say.
Check the wire connector on the throttle body for loose/broken wires and pins or replace the pigtail.
Clean the throttle body.
Relocate the ground from the rear of the passenger head to front.
If they do not clear it, replace the throttle body.

For the P0120/0220 codes you check the pedal sensor wiring and look for water intrusion in the sensor at the pedal.

For yours I would start checking the wiring at the throttle body. The wires on the throttle body like to break inside the connector. Then check the wiring at the gas pedal, replace the pedal sensor, (Do not use a cheap one, get a factory one through a dealer, I have seen a lot of the parts store ones not help the situation) clean the throttle body and clear the codes. If the problem comes back replace the throttle body.

goes into limp mode on my duramax when i stay goin at 65 mph on the freeway its an 01 lb7 furamax just got injectors done what could it be. and fuel pressure is 11,000 should be 23,000

is the check engine light on??

the power loss light on?? that could be a fly by wire failure.

is it the trans or the engine not working correctly

Roy

2003 Silverado 2500 HD 6.0 When I got this truck the instrument cluster was out. I only had volts temperature gas low light and fluctuating oil pressure. Since this was much of an issue for me didn’t fix. It drove fine until it went to reduced power) I will shorten that to RP for rest of post). Since no instrument cluster no display. I didn’t know what was wrong. I made it home and the problem was gone after ignition was off. It began to go to RP off and on for a while took it to a shop that test drove and couldn’t duplicate problem. Seems their solution was to throw a new instrument cluster at it for $500.00. Declined since I remove in 15 minutes and have repaired for less the $200.00. I took bad advice and replaced ECM for $350 and a complex (to me) relearn. Some gauges came back for a few days but RP came back within two weeks. It always went away after turning off key and waiting 30 seconds. It go annoying so Called a mobile mechanic that diagnosed as replace throttle Body (TB). Replaced with a new Japanese import I don't recall the name of but was just as expensive as The GM replacement and the only one new one in stock the day I needed it. Cost $203. Drove fine for close to a year. Thats when I forced myself to learn about it and by a scan tool with Erase Code ability. After numerous YouTube videos and Google Search went through the usual. Checked all g rounds, replaced Accelerator Position Sensor (APS). The driver’s braided ground was broken off at firewall, so I grounded TB, TAC Module (on driver’s firewall) and negative battery lead to alternator bracket. Cleaned both grounds under driver's side frame. Drove okay for a while but got codes 1516 and 2135 about once a week but cleared easy and went away. Had an attempted theft where steering column was wrecked, and some wires pulled off near ignition switch. I pieced the wires and broken plastic together and radio began to not turn on until 20-30 minutes after start-up ran okay for several months. Reduced power got worse and after I replaced water pump and radiator became every time, I started the engine. I must have damaged wiring harness disconnecting from TB when changing radiator had to turn off or clear codes 1516 and 2135. Also 0120 and 0220 began to appear. Found a wire to TB harness at 90 angle and only a few strands of wire still connected. Instead of just replacing the one pin changed the entire wiring harness connector. I bought one at NAPA recommended and sliced in with supplied slice connectors and shrink wrap. The Japanese Throttle body has blade connectors and new harness pig tail did quite go on all the way and snap in like replaced one. It did go on and problem went away for several months. Now its almost too much. Every time I start it the first code is 0120. Clear. Within 20 seconds 1516 or 2135. After warming up gets better but I have to drive with meter in my lap to clear codes when check engine light comes on. Also get 0332 and 1515 sometimes. Been going off and on for over two years. The TAC module is about the only thing not replaced. Maybe a bad wire somewhere or possible reflash replaced ECM? MAP sensor? Cleaned the battery box and even made an attempt at grounding ECM to negative battery lead. Stuck.

All these codes are related to the 5-volt signal that is sent to the throttle body. Basically, if the 5-volt signal is not correct then the reading that is returned is not going to be correct so the PCM will not know where the throttle is.

I am attaching the testing that we need to run through.

We could pick any of these codes and follow it through as they are each saying something slightly different and at this point could be related to the poor connection that you appear to have.

If they are, then you may have fixed it with the replacement throttle but now have these issues with this part.

Please run through the testing that we need to run through but here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-check-wiring

Please see the testing attached below. Thanks