205 si fault code reset

[MarkWK]

Does anyone know how to rest the fault codes on a 205 si without a proper scan tool?

I have read the codes by grounding out one pin from the green connector, but I think the list I have may include older faults.

For example I have tested the output of the throttle potentiometer, and found it gave good readings. However, I unplugged it the previous day, and it has also shown as one of the faults.

I have a miss firing engine and I’m trying to find out the current faults on the system….

For anyone’s interest, the codes so far are listed below-

12 start test
13 inlet air thermistor
33 inlet manifold pressure sensor
21 throttle potentiometer
52 mixture regulation
41 engine speed sensor
11 end test

 

[MarkWK]

Does anyone know how to rest the fault codes on a 205 si without a proper scan tool?

I have read the codes by grounding out one pin from the green connector, but I think the list I have may include older faults.

For example I have tested the output of the throttle potentiometer, and found it gave good readings. However, I unplugged it the previous day, and it has also shown as one of the faults.

I have a miss firing engine and I’m trying to find out the current faults on the system….

For anyone’s interest, the codes so far are listed below-

12 start test
13 inlet air thermistor
33 inlet manifold pressure sensor
21 throttle potentiometer
52 mixture regulation
41 engine speed sensor
11 end test

So an update, easy enough to reset- disconnected the battery, foot on brake peddle to drain any residual power.

Reconnected and retested- all faults cleared

Ran the engine, retested and one fault returned-

12 start test
13 inlet air thermistor
11 end test

Would a faulty air inlet thermistor be enough to make the car run really rough in all operating temps and revs?

 

[matara]

Just been throught the same on my 91 Si and ended up with the same inlet air themistor fault. I got a replacement sender and installed, cleared it again and its gone away. Saying that my car was running fine before, I just got the check engine light coming on intermittently., so will report back once we drive it a but if the fault has gone away completeley.

It was running really bad and misfiring, and a new set of plugs fixed the problem. I had gotten water down the bores when power washing the engine and I asuume if must of cracked one of the plugs.

 

[MarkWK]

Just been throught the same on my 91 Si and ended up with the same inlet air themistor fault. I got a replacement sender and installed, cleared it again and its gone away. Saying that my car was running fine before, I just got the check engine light coming on intermittently., so will report back once we drive it a but if the fault has gone away completeley.

It was running really bad and misfiring, and a new set of plugs fixed the problem. I had gotten water down the bores when power washing the engine and I asuume if must of cracked one of the plugs.

Thanks Matara,

I have tested the sensor and it’s definitely bad. No readings from it at all (does have a supply voltage).

Looking at it there’s a hair line crack all around the sensor.

I had no warning light, just mis firing- changed coil and plugs with no change (leads on order, but I don’t think that’s the problem)

Ordered a new air inlet sensor, hopefully here for the weekend, I’ll report back when it’s fitted….

 

[run205]

"I have read the codes by grounding out one pin from the green connector"

mark, out of interest, how'd you get your codes ?

not questioning them at all, I just didn't understand how you got them without some kind of readout ?

 

[MarkWK]

"I have read the codes by grounding out one pin from the green connector"

mark, out of interest, how'd you get your codes ?

not questioning them at all, I just didn't understand how you got them without some kind of readout ?

There is a green 2 pin connector on the in the engine bay, drivers side near the bulkhead.

I ran a wire from one pin of this connector into the cabin.

With the ignition on (engine not running) held the other end or the wire against the key/ignition barrel for between 3-5 seconds to ground it out.

The engine warning light should go out, then pulse once with a 1.5 second gap then pulse twice with a 1 second gap. 1 pulse + 2 pulses equals 12 - ‘start test’

Ground the cable again, and the engine light will show another sequence

Continue this process until the count is 11 - ‘end test’

I had to go through the sequence about 4 times to get all the codes written down correctly.

There’s a chart on the 205.si site that lists all the fault codes.

However, saying that, after I cleared the old codes, the only code left showed a faulty air inlet thermistor sensor. I tested the sensor and it was definitely faulty, I swapped it for a new working sensor and no change! Still mis firing!!!

I’ll test the map sensor and O2 next I guess….

 

[run205]

thanks, good one
bit like automotive brail

I had symptoms like yours (no code checking though)
it was the spark plug leads on mine but I think you said you've checked that already

 

[MarkWK]

thanks, good one
bit like automotive brail

I had symptoms like yours (no code checking though)
it was the spark plug leads on mine but I think you said you've checked that already

Yes it was a bit!

So, I've changed the air inlet thermistor- no fault codes!

Did it make any difference at all to the rough running of the car- Nope, none at all!

I haven't changed the leads yet, although I think they are good, I have a set on order anyway.

I'm now thinking it might be a blocked Catalytic converter. I I need to get a back pressure gauge and check, but it's either $587 from Supercheap, or wait a month from Aliexpress at $30!

I would have disconnected the cat and seen how it runs or attempted to 'clean' it out, but a previous owner in their wisdom has welded the entire exhaust system together! and so it goes on....!