Test A5 - Knock Sensor (KS) & Knock Control Unit (KCU)
| Circuit | Breakout Box Pin | ECA Pin | |
|---|---|---|---|
| 2.2L Turbo | |||
| GND | 39, 40, 44 | 3A | |
| KCU | 24 | 2M | |
| KS | NA | NA | |
| VPWR | 37, 57 | 1B | |
1) Checking System Integrity Visually check all wiring, harnesses, connectors and components for evidence of damage, overheating, shorting or looseness. If a fault is found, repair as necessary. If no faults are found, go to next step.
2) Checking KCU Voltage Install breakout box. With key on, measure voltage between test pins No. 24 and 39 (ground). Start engine and tap lightly on engine lifting "eye" bracket with a small hammer while varying engine speed between 2500 and 4000 RPM. Voltage should be 3.3-5.0 volts and decrease when engine is tapped with hammer. If not, go to next step.
3) Checking KCU Signal Disconnect KCU connector. With connector removed, attach jumper wires between GND, KS and VPWR terminals. Leave KCU wire disconnected. Measure voltage between KC unit KC terminal and ground. Start engine and tap lightly on engine lifting "eye" bracket with a small hammer while varying engine speed between 2500 and 4000 RPM. If voltage is 3.3-5.0 volts and decreases when engine is tapped with hammer, repair KC wire between KC unit and ECA. If not, go to next step.
4) Checking VPWR At KC Unit Disconnect KCU connector. Turn key on and measure voltage between KCU VPWR wire and ground. If voltage is greater than 10.0 volts, go to step 5. If voltage is less than 10.0 volts, go to TEST A6.
5) Checking KCU Ground Circuit Disconnect KCU connector. Turn key on and measure voltage between KCU KC wire and ground. If voltage is greater than 10.0 volts, go to step 6. If voltage is less than 10.0 volts, repair KCU GND wire.
6) Checking KC Circuit Disconnect KCU connector. Set VOM on AC scale. Turn ignition on. Measure AC voltage between KCU KS wire and ground. Tap lightly on engine lifting "eye" bracket with a small hammer. If voltage is more than .03 volts when engine is tapped with hammer, replace KCU. If NOT, go to next step.
7) Disconnect knock sensor connector. Set VOM on AC scale. Measure AC voltage between knock sensor KS wire and ground. Tap lightly on engine lifting "eye" bracket with a small hammer. If voltage is more than .03 volts when engine is tapped with hammer, repair KS wire to KC unit. If not, replace knock sensor.