Engine Power Is Reduced - Ongoing Issue, Updates throughout thread.
- Thread starter Mighty Hd
- Start date
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swathdiver
Full Access Member
You might consider plugging that back in and using a battery tender. Almost seems like the car was struck by lightning. The wiring and grounds are good but the modules/computers are all going bad it seems.
There are a few guys on here out your way, some in Plant City, Davenport, Haines City and Sugarloaf Mountain.
Mighty Hd
Full Access Member
I have been using a battery tender off and on without incident.
We haven’t had any thunderstorms in this area for weeks; This all started when we were driving to GA the week of Christmas. We made a quick stop in Folkston and then it wouldn’t restart. It was raining, no lightning…..
I got it going again and made it to the local Advance to clear the codes; afterwards we cut our trip short and made a bee-line back home.
I swapped the fuel pump (low PSI) and the control module. It was fine for about a week and now suddenly going into reduced power mode.
Yesterday it went into limp mode with no codes after I cleared the initial 6000 that showed up.
We haven’t had any thunderstorms in this area for weeks; This all started when we were driving to GA the week of Christmas. We made a quick stop in Folkston and then it wouldn’t restart. It was raining, no lightning…..
I got it going again and made it to the local Advance to clear the codes; afterwards we cut our trip short and made a bee-line back home.
I swapped the fuel pump (low PSI) and the control module. It was fine for about a week and now suddenly going into reduced power mode.
Yesterday it went into limp mode with no codes after I cleared the initial 6000 that showed up.
Why not pull the battery and take it to have tested as @swathdiver suggested?
with that many codes I would have to guess there is a short in the lan buss or a module is bad or going bad works until it gets warmed up then shorts out.
it's probably going to take a deeper diagnostic to figure out. meaning like testing on the lan buss with a scope and that takes a certain skill set.
just my .02
it's probably going to take a deeper diagnostic to figure out. meaning like testing on the lan buss with a scope and that takes a certain skill set.
just my .02
Mighty Hd
Full Access Member
I did that last week. I have an analyzer at home and also took it to advance auto. no issues found.
Mighty Hd
Full Access Member
I’m out for a drive now. Drove it long enough to get it out of closed loop. Stopped for lunch and we’ll see
Noticed the idle is a bIt erratic. TB was cleaned yesterday and I did a release as well.
Maybe check the fuse box, pull it off and see if there is any corroded pins.
Mighty Hd
Full Access Member
Did that this morning. Everything looks good.
Mighty Hd
Full Access Member
Well, the saga continues.
I replaced the terminal ends of the negative ground cable from the battery to the block/front bumper and discovered the inside of the cable was black and had a green dusty substance as well.
Installed the new battery to block/frame ground today. Frame grounding points are clean. The secondary ground at this same location looked good, but i went ahead and put a new terminal end on it as well.
I also re-did the ground wire under the driver side door; removed the end and spliced in a new loop terminal.
Everything was good, let it run and all the codes were gone with the exception of the transfer case.
After a hot -soak and restart, “engine power is reduced” message is back again.
FML.
Removed the top cover of the dash and verified the ground wires were clean and secure.
So the following has been performed:
Throttle Body (new OEM)
Negative Battery cable (OEM)
Battery is good
Every ground checked, cleaned and reassembled.
No evidence of wire damage
Fuses / relays all pulled and verified there is no corrosion
WHAT am I missing?
I’m half temped to either take it to the dealer or just sell the damn thing.
I replaced the terminal ends of the negative ground cable from the battery to the block/front bumper and discovered the inside of the cable was black and had a green dusty substance as well.
Installed the new battery to block/frame ground today. Frame grounding points are clean. The secondary ground at this same location looked good, but i went ahead and put a new terminal end on it as well.
I also re-did the ground wire under the driver side door; removed the end and spliced in a new loop terminal.
Everything was good, let it run and all the codes were gone with the exception of the transfer case.
After a hot -soak and restart, “engine power is reduced” message is back again.
FML.
Removed the top cover of the dash and verified the ground wires were clean and secure.
So the following has been performed:
Throttle Body (new OEM)
Negative Battery cable (OEM)
Battery is good
Every ground checked, cleaned and reassembled.
No evidence of wire damage
Fuses / relays all pulled and verified there is no corrosion
WHAT am I missing?
I’m half temped to either take it to the dealer or just sell the damn thing.
Is your battery an AGM? I just went through a whole series of electrical gremlins on my Infiniti G35X, which had a 10 month old AGM battery from Advanced Auto. Took it to them for testing and it all tested fine on their 1990s tech battery/charging system tester so they wouldn't replace the battery. Just the same, I went down the street to Autozone and bought a new conventional lead-acid battery and put it in. All problems magically fixed themselves.
Mighty Hd
Full Access Member
New negative battery cable is on
Positive cable is good and cleaned
New 170 amp mega fuse
Ground terminal ends have all been replaced, crimped and heat shrink sealed:
- LT / RT front frame rails behind the bumper
- LT under driver door
- LT rear at the rear body mount
New OEM ground strap LT engine head to firewall
New throttle body
New gas pedal
New mass air flow sensor
New MAP Sensor
Removed all wiring from the wire loom, no wires are damaged. New wire loom
Dielectric grease on the PCM connection, throttle body connection, MAF connection and all ground points.
Removed the Blackbear tune and reprogrammed the factory engine / trans tune.
Still getting “Engine Power is Reduced”
Obviously with the factory tune I can’t drive it so I put the Blackbear tune back on, which prevents it from fully going into limp mode.
It happens only after a hot soak. Ie: Driven for 5-10 miles, full warm up. Sit for an hour or so and restart. Triggers a ton of codes and engine power is reduced. It was initially intermittent. Now it is much more frequent.
My next two options are to either trade it or take it to the dealer and fix it. Real ******* as I just redid the entire brake system and put new tires on within the last 5,000 miles.
Positive cable is good and cleaned
New 170 amp mega fuse
Ground terminal ends have all been replaced, crimped and heat shrink sealed:
- LT / RT front frame rails behind the bumper
- LT under driver door
- LT rear at the rear body mount
New OEM ground strap LT engine head to firewall
New throttle body
New gas pedal
New mass air flow sensor
New MAP Sensor
Removed all wiring from the wire loom, no wires are damaged. New wire loom
Dielectric grease on the PCM connection, throttle body connection, MAF connection and all ground points.
Removed the Blackbear tune and reprogrammed the factory engine / trans tune.
Still getting “Engine Power is Reduced”
Obviously with the factory tune I can’t drive it so I put the Blackbear tune back on, which prevents it from fully going into limp mode.
It happens only after a hot soak. Ie: Driven for 5-10 miles, full warm up. Sit for an hour or so and restart. Triggers a ton of codes and engine power is reduced. It was initially intermittent. Now it is much more frequent.
My next two options are to either trade it or take it to the dealer and fix it. Real ******* as I just redid the entire brake system and put new tires on within the last 5,000 miles.
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Mighty Hd
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Mighty Hd
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Mighty Hd
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Just Fishing
Can't fix stupid
What happens if you do the heat soak repro with the hood open?
Might be a way to start blaming the ecm since it's under the hood.
Might be a way to start blaming the ecm since it's under the hood.
Mighty Hd
Full Access Member
We have had some cooler weather, it is not doing it nearly as frequently. Specifically when it’s cold – cold for Florida under 60° – it will do it every few days.
I put the factory tune back on the ECM and the TCM end still getting the error. It comes up and says “engine power is reduced “and then disappears. No codes. However I’m getting a ton of fault codes. Nothing that illuminates the malfunction indicator lamp
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