computer codes

[Robert Richards]

does anyone know the codes for a mk1 4age and what ones to check cause i dont have a obd1 scanner i heard you can use a paper clip

[Bigbacon]

what year? the codes are different.

Either way, how to check them is the same. I would suggest you get the repair manual PDF from the link in my signature. and yes, you do use a paper clip. these cars are not OBD vehicles.

[Robert Richards]

its an 87
thanks

[muffinman]

A little bit of searching can go a long way.

The early MK1 codes are different, here are the procedures and codes.
Check codes with the throttle closed, transmission in neutral, all accessories off, and engine at normal operating temperature.
Turn ignition to ON but do not start,
Short T - E1 on service connector,
The check engine light will flashing indicating the codes.
Normal code is 1 flash every 5 seconds or so.
Fault codes will read in ascending order, - code - 2.5 second pause - code - 2.5 second pause - code, etc. until all codes are read.

1 = Normal (No codes recorded)
2 = AFM signal (Open in VC, VS, VB, or E2 or short in EC)
3 = Ignition signal (no signal from igniter 4 times in a row)
4 = water temp sensor (fault in coolant temp. sensor circuit)
5 = O2 sensor (open in O2 sensor - lean signal only)
6 = RPM signal (No Ne, G signal within several seconds after start)
7 = TPS (circuit fault in TPS signal)
8 = Intake air temp sensor (fault in intake air temp sensor circuit)
9 = (There is no 9)
10 = Starter signal (no STA signal before engine reaches 800 RPM)
11 = Switch signal (AC switch on, TPS idle switch off, or AT shift in D during check)

This is for the early NA MK1s.

That's quite a collection ...
Here are the codes for the 88-89 MK1 including the SC.

1988 – 1989 4AGE
Code No.
12. RPM signal
13. RPM signal
14. Ignition signal
21. Oxygen sensor signal/oxygen sensor heater
22. Water temperature sensor signal
24. Intake air temperature sensor signal
25. Air-fuel ratio lean malfunction
26. Air-fuel ratio rich malfunction
31. Air flow meter signal
41. Throttle position sensor signal
42. Vehicle speed sensor signal
43. Starter signal
51. Switch signal
71. EGR system malfunction

1988 – 1989 4AGZE
Code No.
11. ECU (+B)
12. RPM signal
13. RPM signal
14. Ignition signal
21. Oxygen sensor signal/oxygen sensor heater
22. Water temperature sensor signal
24. Intake air temperature sensor signal
25. Air-fuel ratio lean malfunction
26. Air-fuel ratio rich malfunction
31. Air flow meter signal
32. Air flow meter signal
41. Throttle position sensor signal
42. Vehicle speed sensor signal
43. Starter signal
51. Switch signal
52. Knock sensor signal
53. Knock control signal in ECU
71. EGR system malfunction

[saitotiktmdog]

Not trying to hijack But I am getting error code 11 and it wont go away. The interesting thing is that the engine light doesn't come on when the car is running, at least it did not last night. Car was an 86 auto that has been converted to a manual. I am running the manual engine harness using the auto engine computer. If I hook up the manual ecu it flashes code one (everything ok) when jumped but runs like garbage. It will idle but thats it. It runs better with the auto ecu. I think it might be tps related. I am also wondering if tps and afm are computer specific. Would a manual tps work with an auto ecu for example.

The issue I have when the auto ecu is that when I short T and E1 The idle does not change. When I check timing shorted or not shorted it hovers around 10 degrees. I am thinking it might be the code I cant get to go away causing the idle not to default. Any input would be great.

[Bigbacon]

Saitotiktmdog: make sure your throttle positioning sensor is working and is with in the books specifications. Code 11 is normally TPS related.

[muffinman]

could also be that the auto ecu thinks that the car is in gear.

11 = Switch signal (AC switch on, TPS idle switch off, or AT shift in D during check)

[saitotiktmdog]

Made some edits to my first post to clarify things. I cant get code 11 to go away and with the manual computer I get code one which is everything is ok, but it is not because it runs terrible.