Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

1988 Audi 80 Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Fault Codes

FAULT CODE

Code Number

Description

Code 1111

Defective ECU

Code 2113

No RPM signal from Hall sensor or airflow sensor plate not moving freely

Code 2121 ⁽¹⁾

Defective idle switch

Code 2123

Defective full throttle switch

Code 2141

Knock control is at control limit

Code 2142

Knock Sensor signal

Code 2231 ⁽¹⁾

Adjustment limits of idle stabilization exceeded

Code 2232

Airflow Sensor potentiometer

Code 2312

Coolant Temperature Sensor

Code 2341

O2 sensor control at control limit

Code 2342

O2 sensor control

Code 2343 ⁽¹⁾

Adjustment limits of fuel mixture exceeded (too lean)

Code 2344 ⁽¹⁾

Adjustment limits of fuel mixture exceeded (too rich)

Code 4431 ⁽¹⁾

Idle Stabilizer Valve

Code 4444 ⁽¹⁾

No faults recognized

Code 0000

End of fault output display

⁽¹⁾	Codes are set in temporary fault memory only.

Chapter Navigation

Return to Chapter: Testing

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready Tools Compare Repair Quote Quote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.