Daewoo Matiz - Check engine light puzzle

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Sat 10 Sep 2016 14:25
Daewoo Matiz - Check engine light puzzle - rustonboy

After putting up with the dreaded 'check engine' light (MIL) for a while, I paid £24 to have the code read by a local garage. They found the code P0480, which is apparently due to a Low Speed Cooling Fan Relay Circuit Fault.

Having checked that the high-speed fan circuit works by switching on the air conditioning, the garage cleared the fault code and advised me to keep an eye on the temperature gauge (which always looks fine at just below half way once the engine has warmed up).

However, the MIL lit up again as I was driving home from the garage. I decided to invest in a gadget from Amazon called ODBMATE OM123, which cost about £26. It plugs into the diagnostic socket under the glove compartment, and allows you to read and erase the check engine codes, and see data about your engine in real time (e.g. rpm, temperature, etc.).

But my MIL kept coming back with the P0480 code every time I erased it, and I naturally fretted about the engine possibly overheating due to this fault.

Then I cleared the check engine light an sat on the drive with the engine running while listening carefully, and watched the live data feed telling me the temperature of the engine. I could hear the low-speed fan switching on and off periodically. It comes on at about 93 degrees C and switches off again at about 88 degrees C. So clearly works and is operated by some sort of thermostat. And the check engine light stayed off. I was relieved and thought my problems were over.

But the check engine light came on again as soon as I set off and got 100 yards down the road, and the same error code P0480 showed up on the scanner again.

Mysterious points:

1) The service manual says that this DTC should not illiminate the MIL, but it does for me.

2) The fan seems to work be working perfectly well, yet the DTC reappears every time I clear it.

3) The DTC/MIL does not come on if I just sit on the drive with the car running. It only occurs after a minute or two driving.

Well if anyone out there has any ideas, I would be really grateful to hear them.

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Sat 10 Sep 2016 17:48
Daewoo Matiz - Check engine light puzzle - elekie&a/c doctor

I think I would use a different scan tool.The info displayed may be incorrect and steering you in the wrong direction.

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Sun 11 Sep 2016 00:04
Daewoo Matiz - Check engine light puzzle - Bolt

Not sure if this will help

www.mymatiz.com/manual/

I had a Kalos with the same problem and was a relay fault. which is part of the fault code you have

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Mon 12 Sep 2016 18:15
Daewoo Matiz - Check engine light puzzle - rustonboy

Not sure if this will help

www.mymatiz.com/manual/

I had a Kalos with the same problem and was a relay fault. which is part of the fault code you have

Thank you for your help and the link. I will check the manual and maybe try swapping the relays around to see whether that has any effect. Most of them seem to have the same part number on top, so I guess it's a standard part. Did you solve the problem by buying a new relay? Thanks again :-)

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Mon 12 Sep 2016 22:32
Daewoo Matiz - Check engine light puzzle - Bolt

Not sure if this will help

www.mymatiz.com/manual/

I had a Kalos with the same problem and was a relay fault. which is part of the fault code you have

Thank you for your help and the link. I will check the manual and maybe try swapping the relays around to see whether that has any effect. Most of them seem to have the same part number on top, so I guess it's a standard part. Did you solve the problem by buying a new relay? Thanks again :-)

I`ve no idea of price now but I paid £8 for it from a local motor factors which worked a treat, untill the engine siezed up (nothing to do with relay)

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Mon 12 Sep 2016 18:10
Daewoo Matiz - Check engine light puzzle - rustonboy

I think I would use a different scan tool.The info displayed may be incorrect and steering you in the wrong direction.

Thank you for your good advice and wise words - I see your logic. But with the garage scan tool and mine both reporting the same fault, and a further fee from a different garage to check it again ... oh no ... I did not buy a 54 plate Matiz cos I am rich :-)

However, I think I will end up taking your advice after pay day :-)

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Mon 12 Sep 2016 19:10
Daewoo Matiz - Check engine light puzzle - Railroad.
Low Speed Cooling Fan Circuit Fault. Well there's your clue. The relay will have a live and an earth to the energising coil, and a live and an output at the contacts. The ECM will provide either the live or the earth at the coil whilst the other is permanent with ignition on. One of these is missing, and this should not be difficult to check.
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