2004 Chevrolet TrailBlazer Logo
DALE RIGGLE Posted on Feb 06, 2013
Answered by a Fixya Expert

Trustworthy Expert Solutions

At Fixya.com, our trusted experts are meticulously vetted and possess extensive experience in their respective fields. Backed by a community of knowledgeable professionals, our platform ensures that the solutions provided are thoroughly researched and validated.

View Our Top Experts

2004 trailblazer code po128

Yea my check eng light came on it is code po128 how do i fixes it

1 Answer

Thomas Perkins

Level 3:

An expert who has achieved level 3 by getting 1000 points

Superstar:

An expert that got 20 achievements.

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

  • Chevrolet Master 15,088 Answers
  • Posted on Feb 06, 2013
Thomas Perkins
Chevrolet Master
Level 3:

An expert who has achieved level 3 by getting 1000 points

Superstar:

An expert that got 20 achievements.

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

Joined: Feb 12, 2010
Answers
15088
Questions
0
Helped
3388271
Points
54869

P0128:
P0128 OBD-II Trouble Code
Technical DescriptionCoolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

What does that mean?This means that the engine's PCM detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine. The intent of the P0128 code is to indicate a faulty thermostat. Similar codes: P0125

In determining the engine did not reach a "normal" temperature, it takes into account the length of time the vehicle has been running, the intake air temperature (IAT) sensor reading, the engine coolant temperature (ECT) sensor reading, and the speed of the vehicle.

CausesA code P0128 may mean that one or more of the following has happened:

Low engine coolant level .
Leaking or stuck open thermostat .
Faulty cooling fan (running too much) .
Faulty coolant temperature (ECT) sensor.
Faulty intake air temperature (IAT) sensor .Here's a link on replacing your thermostat.

5 Related Answers

Anonymous

  • 104 Answers
  • Posted on Apr 20, 2010

SOURCE: chevy trailblazer check engine light

P0128 is coolant operating temperature operating too low. This can be contributed to the Thermostat stuck open or faulty electronic radiator fan clutch. This is common, I had the same issue and replaced the thermostat and fan clutch and had the clutch re-programmed (required) at the dealer. As for the P0410, check the air pump fuse, if blown it will set this code on. Also check the air pump hoses for water and cracks. Hopefully this helps!!

Ad

Anonymous

  • 677 Answers
  • Posted on Feb 12, 2010

SOURCE: I have serv eng light on with code # PO172 , PO128

Code p0172 is MAF, vacuum leak, and fuel pressure.
You can see my TIPS on this site to help with the MAF.
Code p0128 is Low ccolant, ECT or the IAT.
code p0442 is your EVAP system.
Please let me know what you find.

Anonymous

  • 1201 Answers
  • Posted on Aug 29, 2009

SOURCE: what do I need to do to fix my 2005 trailblazer.

Change the coolant temperature sensor. If the code is still there, change the thermostat, it might be stuck open causing the engine to run cooler than it should.

Testimonial: "ty so much, could I ask where is the sensor ? Im sorry to be a bother..."

Anonymous

  • 1450 Answers
  • Posted on Nov 11, 2008

SOURCE: po128 code on 2001 corvette

replace the thermostat. computer sees engine is running too cool thermostat stuck open.

Anonymous

  • 8197 Answers
  • Posted on Jul 12, 2010

SOURCE: i have a 05 chevy

P0410

Definition
Secondary Air Injection System fault
Explanation
The air injection system is monitored for faults
Probable Causes
1) Circuit relay defective or fuse open
2) Check connector and wiring
3) AIR pump defective or hoses blocked


P0128
Fault Code Definition

  • Engine temperature has not increased and/or reached the correct level within a specified amount of time after engine startup
Common Problems That Trigger the P0128 Code
As for the po128 I would replace the thermostat first. That is the problem 99% of the time.

Good Luck

Ad

Add Your Answer

×

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

0helpful
1answer

2004 buick rainer, po128 pending has heat the check engine light comes on and goes out temp is 195

PO 128 is a coolant temperature beyond threshold code. It means your thermostat is stuck and needs to be replaced.
0helpful
1answer

How can a 2004 4.2 trailblazer timing chain jump time?

No not really. Unless there is a major failure. These are bad for the chain guides.. Made of plastic and wearout...Not an easy fix..You have to tear apart the top of the engine and the bottom of the engine to fix it. Takes me about 8 hours, I've done a few of them.
0helpful
1answer

Engine code po128

change your thermostat, and while you are down there, suggest you change your coolant temp senor too Engine is running too cold (rich)
0helpful
1answer

Check engine light on. Won't stay off. OCD code is po442 po128 coolant.

Just fixed mine with the same code and gm tech advised me to change thermostat which is not a fun job as it is located in the LOWER hose and comes with a gooseneck assembly and O ring.The temp sensor could also be the problem but was told not likely so got by with just thermostat!
0helpful
1answer

Code po128 coolant thermostat

Replace the thermostat/ housing assy
1helpful
1answer

What could cause code PO128 to come up on a 2002 Chevy Trailblazer

Sounds like the thermostat may be stuck open or has anyone put a colder thermostat in the car,because once it starts to get cold it will throw a SES with a colder then stock thermostat.

Code PO128; coolant temp below thermostat regulating temp. Replace the thermostat and that should address your issue.

Thank you for using fixya and good uck
0helpful
1answer

I have serv eng light on with code # PO172 , PO128 , and PO442 , and I replaced fuel tank cap today , light still on ,and I need to get inspection , but I am out of work and can't afford expensive repair...

Code p0172 is MAF, vacuum leak, and fuel pressure.
You can see my TIPS on this site to help with the MAF.
Code p0128 is Low ccolant, ECT or the IAT.
code p0442 is your EVAP system.
Please let me know what you find.
2helpful
1answer

What do I need to do to fix my 2005 trailblazer. its reading a code po128

Change the coolant temperature sensor. If the code is still there, change the thermostat, it might be stuck open causing the engine to run cooler than it should.
0helpful
1answer

I have a 2004 Chevrolet Trailblazer. What would

Is there a codes set or" Service Eng Soon" light on? Does it feel like a misfire?
Not finding what you are looking for?

3,487 views

Ask a Question

Usually answered in minutes!

Top Chevrolet Experts

ZJ Limited
ZJ Limited

Level 3 Expert

17989 Answers

john h

Level 3 Expert

29494 Answers

Thomas Perkins
Thomas Perkins

Level 3 Expert

15088 Answers

Are you a Chevrolet Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...