Audi 80 Quiz
MPI and MPFI Injection Systems

Fault Code List - MPI/MPFI Fuel Injection Systems

In this manual: MPI and MPFI Injection Systems
Technical Description — 39Engines — 41Exhaust System — 13Cooling System — 28Fuel tank and fuel pump — 12Air Filter and Intake Ducts — 13Mono-Motronic Injection System — 18Digifant Injection System — 19KE-III-Jetronic Injection System — 35MPI and MPFI Injection Systems — 32Clutch — 11Transmission and Driveline — 21Suspension and Steering — 33Brake System — 41Anti-lock brake system — 8Wheels and Tires — 13Body Electrical System — 35Ignition System — 24Lighting — 14Signaling Devices — 7Instruments and Auxiliary Equipment — 54Heating and Ventilation — 7Body Components — 18Troubleshooting — 6Specifications — 13
~2min read

Malfunction Possible Cause Remedy
A. Cold engine does not start at all or starts with great difficulty 1. Defective fuse 13, 21, 27, 28 or 32
2. Defective fuel pump relay
3. Fuel pump does not supply fuel at all or supplies very little
4. Defective fuel pressure regulator
5. Defective idle air control valve
6. Defective control unit
7. No engine speed signal from engine speed sensor
8. Unmetered air enters the engine		 Replace
Check, replace if necessary
Is there any fuel in the fuel tank at all?
Check pump, measure fuel delivery quantity (Refer to Fuel Tank and Fuel Pump chapter)
Measure pressure in workshop
Check
Check in workshop
Check cable routing
Check all lines
B. Warm engine does not start at all or starts with difficulty 1. Vacuum line to fuel pressure regulator is defective
2. See A 1 – 4, 6 and 7
3. Injectors leak
4. Defective coolant temperature sensor		 Check line
Check injectors
Check sensor
C. Engine starts but stalls again 1. See A 1 and 5
2. See B1
3. CO value differs from specification
4. Defective air flow meter (MPI), or intake air temperature sensor or manifold pressure sensor (MPFI)
5. Defective throttle valve potentiometer		 Check injection system
Check
Check
D. Cold engine shakes at idle 1. See A 5
E. Warmed-up engine shakes at idle 1. See A 4 and 5
2. See C3
F. Idle speed too high See A 5
G. Engine runs unevenly 1. Fuel filter clogged
2. See A3 and 5
3. See B34, see C3 and 4		 Replace the filter
H. Engine runs unevenly, stalls Fuel pump operates unevenly Check fuel pump delivery rate
I. Insufficient engine power 1. See A3, 4 and 8
2. See C3 and 5
3. Throttle valves do not move to full-throttle position		 Adjust accelerator cable
J. Backfiring in exhaust manifold 1. See A4
2. See C3
K. Fuel consumption too high 1. See B4
2. See C3

Test yourself

A quick Audi 80 quiz: every answer comes with an explanation and a link to the manual page.