fault CODES HELP! please

[quk@sievers.com (Phil Payne)]

In message <m0uqlsx-000FkjC@post.cis.smu.edu> Robert Paul Andrews writes:

> I just started to have problems with my Check engine light coming on.  It
> will not stay on, just flicker on and off.  It seems to do it during sitting
> in traffic and with a hot engine.  I plugged a fuse in the fuel pump relay
> to get the codes and all it dumped on me was this :  3 short blips, pause, 1 
> blip, pause again, then the pattern just repeated.

You didn't say which vehicle or configuration.  The following is my own 
personal translation of the factory documentation for the ur-quattro.  If 
anything you have read differs from this, ignore it.  If your vehicle is not an 
ur-quattro, we'll have to think again:

Audi quattro self-diagnosis (MB engine)

The term "self-diagnosis" refers to electronically
controlled systems that are equipped with an error code
storage system.

Problems encountered while driving are logged in the
control unit's storage.  The contents are retained only
while the ignition is switched on, i.e., if the ignition
is turned off, the error logs are lost.

If an error which could result in engine damage occurs,
this is also signalled via the warning light on the
console.

This warning lamp must illuminate whenever the ignition
is turned on.

If this light does not illuminate when the ignition is
turned on, bridge the contacts on the top of the fuel
pump relay with a spare fuse.  The warning light should
come on - if it does not, trace the wiring according to
the wiring diagram.

Reading the error codes.

The error codes can be read from the engine electronics
warning light.  Each code consists of four groups of
pulses.  There is a pause of around 2.5 seconds between
each group.  The pulses in each group are counted (there
are never more than four) to derive a four-digit code.
These are listed below.

The exact sequence for each code is a start sequence of
2.5 seconds with the lamp on, and 2.5 with it off.  The
codes then follow as half-second pulses separated by half-
second gaps, with a larger gap of 2.5 seconds between
each group.  The sequence is repeated until the system is
stepped to the next error log by bridging the contacts on
the fuel pump relay.  The lamp blinks at 2.5 second
intervals to indicate that the last error code has been
seen.

The sequence is terminated if the ignition is switched
off or the engine exceeds 2,500 rpm.

Prerequisites

  Fuse 24 OK
  Control unit power OK
  Engine warning lamp OK
  Fuel pump relay OK.

If the engine runs, start it and test drive the vehicle.
The engine should be revved above 3,000 rpm, positive
boost pressure should be used and the accelerator should
be fully depressed at least once.  At the end of the test
drive, do not switch off the engine.

If the engine will not run, turn it on the starter for at
least five seconds.  Leave the ignition switched on, and
proceed as if a test drive has been performed.

With a spare blade relay, bridge the contacts provided
for the purpose on top of the fuel pump relay for at
least 4 seconds.  The engine warning lamp will then pulse
out the first error code.  If there is no error logged,
the system will pulse out "4444", i.e., the warning light
will illuminate once for 2.5 seconds, then go off for 2.5
seconds, then pulse four times at half second intervals.
After a pause of 2.5 seconds, it will again pulse four
times, reading out the second "4".

Note down the error code, if any, and repeat the 4 second
bridging of the fuel pump relay contacts.  The next code
will be displayed.  If the lamp merely flashes at 2.5
second intervals, the last error code has been read out.
If multiple errors have been logged, they should be dealt
with in the order the system reads them out.

Code Source           Possible cause                          Check
1111 Control Unit     Defective processor                     Replace unit
2111 RPM sender       Open or short circuit, defective sensor Sensor & cables 
2112 Timing sender    As RPM, or flywheel peg mislocated      Sensor & flywheel 
                                                              peg 
2113 Hall sender      As RPM, or distributor mislocated       Sensor &
                                                              distributor
2121 Idle switch      As RPM, or switch stuck in position     Switch & cabling
2123 Full load switch As idle switch                          As above
2141 Knock regulator  Fuel octane too low                     Compression, 
                                                              injection,
                                                              boost 
2142 Knock sensor     Open or short circuit, defective sensor Sensor and 
                                                              cabling 
2221 Vacuum hose      Vacuum hose to controller defective     Check hose
2222 Pressure sensor  Control unit pressure sensor defective  Replace unit 
2312 Coolant sensor   Open or short circuit, defective sensor Sensor & cables 
2322 Inlet air temp.  As above                                As above
2214 Over-revved      Engine has exceeded rev limit           Driver
2224 Excess boost     Wastegate or pressure tubing            Wastegate & 
                                                              plumbing


--
 Phil Payne
 phil@sievers.com
 Committee Member, UK Audi [ur-]quattro Owners Club