Fault codes 25 and 52?

Tiny
RJHAMMOND
  • MEMBER
  • 1994 TOYOTA PICKUP
  • 6 CYL
  • 4WD
  • MANUAL
  • 160,000 MILES
Check engine light comes on only after reaching operating temperature with a distinct loss of power. It just bogs down. Will changing out the air and fuel filters fix the mixture and knock issues? If so, the air filter is not a problem but I’m not so confident about the fuel filter. I could use some guidance. Thanks guys!
Friday, August 12th, 2022 AT 3:24 PM

11 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,520 POSTS
So, these codes are for lean mixture and engine knocking, can I ask how the engine sounds when it is running? The fuel filter on these clogs up so I would start with the filters, also can you upload a video of the engine running? If the engine is worn and has an issue such as timing chain guides or piston noise the knock code will not go away. Please let me know. Check out the diagrams (below). Please let us know what happens. The Fuel Filter is Located at the right side of the engine above the starter motor.
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Saturday, August 13th, 2022 AT 9:22 AM
Tiny
RJHAMMOND
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I’ve had this truck for 20 years and it has always ticked when running. Filters are on their way, so I’ll get back to you ASAP. Thanks!
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Tuesday, August 16th, 2022 AT 1:16 PM
Tiny
KEN L
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Thanks for the video, I don't think the engine noise is an issue. It sounds more like an exhaust leak. Also check your MA sensor to see if the flow door moves freely. Let me know after you replace the fuel filter, that should help.
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Wednesday, August 17th, 2022 AT 11:29 AM
Tiny
RJHAMMOND
  • MEMBER
  • 6 POSTS
Hey, just wanted to let you know I haven’t forgotten about you, I’ve just been ridiculously busy. The truck goes in on Wednesday for a new fuel filter. Checked the air and it was like new. Hopefully your fix will be the cure. I won’t fail to let you know. Thanks!
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Friday, September 2nd, 2022 AT 4:38 PM
Tiny
KEN L
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Thanks, it's all we ask for; I want to get this fixed for you.
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Saturday, September 3rd, 2022 AT 11:34 AM
Tiny
RJHAMMOND
  • MEMBER
  • 6 POSTS
So, I picked up my truck Wednesday afternoon after having the fuel filter swapped out (which the mechanic said was pretty clean) and the check engine light came on within a block. I’m going to drop it off Monday morning so he can check it out. Thanks, Rick
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Saturday, September 10th, 2022 AT 6:31 AM
Tiny
KEN L
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It sounds like the ECU is not working correctly, let me know what they say.
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Monday, September 12th, 2022 AT 2:35 PM
Tiny
RJHAMMOND
  • MEMBER
  • 6 POSTS
What is the ECU?
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Tuesday, September 13th, 2022 AT 7:22 AM
Tiny
KEN L
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Sorry the ECM (engine control module) Check out the images (below). Please let us know what happens.
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Tuesday, September 13th, 2022 AT 2:29 PM
Tiny
RJHAMMOND
  • MEMBER
  • 6 POSTS
The mechanic used two different sensors, but the truck would lose contact after about 10 seconds, so he wasn’t able to read the codes. Any ideas?
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Tuesday, September 20th, 2022 AT 6:22 AM
Tiny
KEN L
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Yep, it sounds like the ECM is out, I would try replacing it to fix the problem.
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Thursday, September 22nd, 2022 AT 11:14 AM

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