Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 15 of 15 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter · #1 ·
I have a 2003 trailblazer and have been battling for months with a “reduced engine power” light. I have no throttle. I replaced the gas pedal, the ecm, and the throttle body. I spoke to a mechanic yesterday and he said that I need to erase all the codes to get the proper relearn. How can I erase the codes, I have a cheap code reader, but it doesn’t erase.
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
1,458 Posts
A $12 VeePeak bluetooth obd adapter from amazon and any of dozens of free smartphone apps can read and clear codes.
 

·
Registered
Joined
·
15 Posts
I have a 2003 trailblazer and have been battling for months with a “reduced engine power” light. I have no throttle. I replaced the gas pedal, the ecm, and the throttle body. I spoke to a mechanic yesterday and he said that I need to erase all the codes to get the proper relearn. How can I erase the codes, I have a cheap code reader, but it doesn’t erase.
Go to autozone or oreillys they can scan and reset the code
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
4 Posts
I have a 2003 trailblazer and have been battling for months with a “reduced engine power” light. I have no throttle. I replaced the gas pedal, the ecm, and the throttle body. I spoke to a mechanic yesterday and he said that I need to erase all the codes to get the proper relearn. How can I erase the codes, I have a cheap code reader, but it doesn’t erase.
You can reset your PCM/ECU by pulling fuses #10 and #28 for about 30minutes. Do not disconnect the battery as that will introduce a whole host of other problems into your radio and vent control motors.

I battled with the reduced engine power light for about five years. I even reran the harness from the pedal to the PCM and from the PCM to the throttle body. Nothing. I simply learned to drive around with my OBDII reader plug in so I could quickly clear the codes to be able to drive the Trailblazer. Sometimes it would behave for a couple weeks. Other times just a couple days. Lucky for me, one day it caught fire (tranny fluid overflowing onto exhaust pipe) and I had to total the car. It was a 2002 LTZ. A beautiful vehicle. I replaced it with a 2005 Trailblazer (I already had a 2003 Trailblazer). Never have had problems with Reduced Engine Power light on my two remaining Trailblazers!!!
 

·
Registered
2004 chevy trailblazer_lt
Joined
·
1,419 Posts
The next time you experience a Reduced Engine Power notification, unplug the electronic fan clutch. If the Reduced Engine Power light goes away, then you've found the problem - the electronic fan clutch. The fan clutch shares the same 5 VDC reference voltage that the throttle body uses and when it (the fan clutch) goes bad, it often pulls down the reference voltage. Also, check the cable going to the fan clutch connector from the PCM for wire chaffing, broken wires, etc., as this too will cause the Reduced Engine Power condition to occur.
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
4 Posts
The next time you experience a Reduced Engine Power notification, unplug the electronic fan clutch. If the Reduced Engine Power light goes away, then you've found the problem - the electronic fan clutch. The fan clutch shares the same 5 VDC reference voltage that the throttle body uses and when it (the fan clutch) goes bad, it often pulls down the reference voltage. Also, check the cable going to the fan clutch connector from the PCM for wire chaffing, broken wires, etc., as this too will cause the Reduced Engine Power condition to occur.
I tried that too. No joy. My wife was happier than I when the Trailblazer burned down (the tranny oil cooler inside the radiator ruptured causing it to mix radiator water with transmission fluid which caused the tranny fluid to overflow onto my exhaust pipe and catalytic converter. That was the final straw. It was a great light show until the fire department showed up and rained on our celebration!!!)
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
1,458 Posts
Did those with reduced engine power ever see a code P0493? Service information says that code will also set reduced engine power but I seldom see that mentioned. Granted, that code only sets if the cooling fan hits 6800 RPM, but if one is a leadfoot and winds out the engine with hard acceleration that could happen (the fan turns faster than the engine when locked in).
 

·
Registered
Joined
·
25 Posts
I have a 2003 trailblazer and have been battling for months with a “reduced engine power” light. I have no throttle. I replaced the gas pedal, the ecm, and the throttle body. I spoke to a mechanic yesterday and he said that I need to erase all the codes to get the proper relearn. How can I erase the codes, I have a cheap code reader, but it doesn’t erase.
You can disconnect your battery for 15 minutes and this will reset the codes on your ecm your truck will run a little odd for about and hour worth of driving when you do this so note any odd behavior from this reset is part of the reset if your check engine light is on then once it comes back on the relearn should be done
 

·
Registered
2004 chevy trailblazer_lt
Joined
·
1,419 Posts
Do what SpeedStar61 recommends for resetting codes rather than disconnecting the battery.
 

·
Registered
2004 chevy trailblazer_ls
Joined
·
19 Posts
Probably your catalytic converter.
We had this in my sons after he let his thermostat go unchanged. Clogged it right up. Gutted the cat and drives like a race car.
I think, taking out an upstream o2 sensor to see if it runs better, can be diagnosed.
 

·
Registered
Joined
·
98 Posts
I tried that too. No joy. My wife was happier than I when the Trailblazer burned down (the tranny oil cooler inside the radiator ruptured causing it to mix radiator water with transmission fluid which caused the tranny fluid to overflow onto my exhaust pipe and catalytic converter. That was the final straw. It was a great light show until the fire department showed up and rained on our celebration!!!)
A tranny fluid overflow onto exhaust? Kinda hard to visualize that — but I know the GM return tranny lines rust like crap
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
1,458 Posts
A tranny fluid overflow onto exhaust? Kinda hard to visualize that — but I know the GM return tranny lines rust like crap
Not too hard to see... Dipstick tube right above exhaust. Coolant above boiling point instantly boils when pressure is released because of the failed trans cooler, wouldn't take much steam pressure to push out that dipstick top plug/cap.
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
39 Posts
You can reset your PCM/ECU by pulling fuses #10 and #28 for about 30minutes. Do not disconnect the battery as that will introduce a whole host of other problems into your radio and vent control motors.

I battled with the reduced engine power light for about five years. I even reran the harness from the pedal to the PCM and from the PCM to the throttle body. Nothing. I simply learned to drive around with my OBDII reader plug in so I could quickly clear the codes to be able to drive the Trailblazer. Sometimes it would behave for a couple weeks. Other times just a couple days. Lucky for me, one day it caught fire (tranny fluid overflowing onto exhaust pipe) and I had to total the car. It was a 2002 LTZ. A beautiful vehicle. I replaced it with a 2005 Trailblazer (I already had a 2003 Trailblazer). Never have had problems with Reduced Engine Power light on my two remaining Trailblazers!!!
Your right. Don't mess with battery to get rid of codes. Do what speedstar61 recommends. Look under the front fuse box and follow the schematic for fuses 10 and 28.
 
1 - 15 of 15 Posts
Top