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In message <s41e5dcc.054@wppost.depaul.edu> Alex Kowalski (audial@aol.com) (Law Guest Account) writes: > I don't have the code list with me right now (I'm at work). If you post > what you get I'll mail you back and let you know what the computer says > is wrong. Then you can really start looking. [yawn] Audi quattro self-diagnosis (MB engine - and some others) 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 pulses, 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 and 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's pressure sensor defective Replace unit 2312 Coolant sensor Open or short circuit, defective sensor Sensor and 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 and plumbing -- Phil Payne Committee Member, UK Audi [ur-]quattro Owners Club
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