mlsemi

I got the light today. 993 runs as usual. Still runs with main coil wire removed (so both distributors are running). Any reccommendations before I have it towed to the shop?

jford

I would go out to the local auto parts store and get an OBII reader. They are about $100 then you can check the code yourself and see what it is. After you get the code come back to the board and post the results....lots of advice will be sure to follow. BTW I have 'thrown' a CEL on moe than a few occasions and its always been easily diagnosed with the reader and easily remedied as well. GOod luck.

Jamie

Dave H.

also, if the light is just on, but not flashing, the car is safe to drive to the shop. if it is flashing, you should shut off the engine immediately.

a flashing light is usually misfire related...

96C4S

I had the same problem was a cel code solved it by disconnecting the battery followed by a one hour of hard driving between 4500 and 7000 rpm havent had a code since.

JasonAndreas

If you turn the ignition on and hold the gas pedal to the floor for three seconds (and don't turn the car on) and wait for the CEL to flash and then take your foot off the gas you can read out the fault codes without having to buy a $100 OBD2 reader. The CEL will flash out all emissions related fault codes almost like morse code. If there are no faults the CEL will flash once then pause and then flash 5 more times. If you read out the code anyone here with the workshop manuals can tell you what it means. For instance a faulty oxygen sensor will flash 1-1-2-4.

cabrio993

This place is full of knowledge! Were did you get that from? Do you have any tricks for reseting the light?

becker - 97'C4S

in OBD1 that was the method of reading the codes(flashing light) in OBD2 most likely you'll need a scanner, 993s w/OBD1 are most likely pre-96 models

Cheers

kkim

Wow, this is something I've never heard of before, too. Props to you Jason... an ever overflowing fountain of knowledge. However, it won't reset the code, I bet.

I'm with Jaime... go buy a cheap scanner that can read and also clear the code. That way you can see if it comes back and if it's the same as last time. I just saw one for sale in the Checkers Auto ad for like $85.

Good luck!!

993inNC

Most Autozone/Advanced Auto, whatever you have will also read the codes for free and print out the fault codes for you as well.

JasonAndreas

Kelly has confirmed that the accelerator pedal method only works on MY95 993s but I still think there is an easter egg hiding in the MY96+ cars, most OBD2 based cars do (usually you jumper two pins on the diagnostic connector). In any case here are the codes for MY95. You should have a single flash then a pause, then a single or a double flash. If the flash is double then the fault is intermittent (loose contact) otherwise the fault is constant. And then the following flashes;

11 Supply voltage
14 Engine temp sensor 2
15 Throttle potentiometer
18 Rpm signal
19 Speed signal <- Speedometer
21 Hot Film Mass Air flow sensor
22 Oxygen Sensor (Signal)
23 Oxygen regulation
24 Oxygen sensor
25 Intake Temperature Sensor
26 Ignition timing change
27 Opening winding of idle stabilizer
28 Closing winding of idle stabilizer
31 Knock sensor 1
32 Knock sensor 2
33 Control unit faulty
34 Hall signal
36 Idle CO potentiometer
41 Control unit faulty
42 Fuel pump relay (DME-relay)
43 Tank ventilation relay
44 Air Pump
45 Check Engine warning lamp
51 Injection valve cylinder 1
52 Injection valve cylinder 6
53 Injection valve cylinder 2
54 Injection valve cylinder 4
55 Injection valve cylinder 3
56 Injection valve cylinder 5
67 Ground and plug connections
69 Ground and plug connections


A MAF failure would look like;

FLASH pause FLASH pause FLASH FLASH pause FLASH

mlsemi

0.














































Thanks every one. The pedal nad ingnition method did not produce any flashing. I'm going to get a scanner and read the code, and then i will post it.



.

mlsemi

ok I got the scanner and the code is P0137. Scan book says O2 sensor Circuit low volts (bank 1 sensor 2). What does this mean?

becker - 97'C4S

Michael

That could be: the sensor is loose or making a bad connection and hence the voltage readings are
not as expected, or you have a bad sensor.

Most places will reset the code and teel you to see if it comes back, you can visually inspect the
the connectors which sit on the left side of the engine compartment. Some scanners allow you to run tests on the O2 sensors so you can pinpoint which is the one that is flaking out

Cheers

Rob Kwate

According to the Porsche OBD II Troubleshooting Manual, Diagnostic Trouble Code (DTC) P0137 is "Short circuit to ground at signal wire of oxygen sensor behind catalytic converter or incorrect voltage (cylinders 1-3)"

This will be the oxygen sensor downstream from the catalytic converter on the driver's side of the car. The problem can be in the wiring harness, the oxygen sensor, or the engine control module(ECM). I would check the wiring for any fraying, bare spots, etc. and then the oxygen sensor itself. My guess is that it's one of those and not the ECM. Either way, this can probably be fixed by replacing one oxygen sensor. That's where I'd start anyway. Let us know how it goes. Hope this helps, Rob.

JasonAndreas

Rob,
With the Bosch Hammer when you first turn it on and select vehicle type what function does "2=CARB (ISO)" perform? Is it standard OBD2 diagnostics for cars that support ISO9141-2? I don't have the OBD2 cable and the german instructions I have don't mention anything nor can I find anything online.