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.
1994 Audi 90 CS QuattroFACTORY OEM SERVICE PROCEDURE
Engine Controls - Sensor Operating Range Charts: Introduction
Sensor operating range information can help determine if a sensor is out of calibration. An out-of-calibration sensor may not set a trouble code, but it may cause driveability problems.
NOTE:
Unless stated otherwise in test procedure, perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance.
CLOSED THROTTLE POSITION (CTP) SWITCH RESISTANCE
| Terminals | Ohms @ Closed Throttle | Ohms @ Slightly Open Throttle |
|---|---|---|
| 4 & 6 | 0 | Infinite |
CRANKSHAFT POSITION (CKP) SENSOR RESISTANCE
| Terminals No. | Ohms |
|---|---|
| 1 & 2 | 1000 |
| 1 & 3 | 0 |
| 2 & 3 | 0 |
ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE
| Temperature | Ohms |
|---|---|
| 68°F (20°C) | About 2500 |
| 176°F (80°C) | About 330 |
INTAKE MANIFOLD CHANGE-OVER (IMCO) VALVE SWITCH RESISTANCE
| Terminals No. | Ohms |
|---|---|
| 1 & 2 | 25-35 |
MASS AIRFLOW (MAF) SENSOR TEST
| Condition | (1) Volts | ||||
|---|---|---|---|---|---|
| Key On Engine Off | About 0.3-1.1 | ||||
| Engine Running (2) | About 1.5-3.4 | ||||
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OXYGEN SENSOR (O2S) VOLTAGE
| Condition | (1) Volts | ||
|---|---|---|---|
| Lean | About 0.2 | ||
| Rich | About 0.7 | ||
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THROTTLE POSITION (TP) SENSOR RESISTANCE
| Terminals | Ohms @ Idle | Ohms @ Wide Open Throttle |
|---|---|---|
| 1 & 2 | 1500-2600 | N/A |
| 2 & 3 | 750-1300 | 3600 |
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.