Test Kc - Knock Sensor (KS) & Knock Control Unit (KCU)

NOTE: Enter this test only when a Code 05 is displayed during SELF-TEST procedure, or when directed here from another CIRCUIT TEST. This test is intended to diagnose only KCU and KS circuits.

Fig 1: Identifying Knock Control Circuit & Connector Terminals

CIRCUIT PIN IDENTIFICATION

Circuit

Breakout Box Pin

ECA Pin

2.2L Turbo

KCU

⁽¹⁾

⁽¹⁾ **

VPWR

37, 57

GND

39, 40, 44, 60

⁽¹⁾	Breakout box and ECA pin terminals are not available on this vehicle.

1) Checking System Integrity Visually check all wiring, connectors and components for evidence of damage, shorting or looseness. If a fault is found, repair as necessary. If no fault is found, go to step 2).

2) Checking KCU Voltage Turn ignition off. Install breakout box, leaving ECA disconnected. Turn ignition on. Measure voltage between test pin No. 24 and ground. Start engine. Tap lightly on engine lifting eye bracket with 4-oz. hammer while varying engine speed between 2500 and 4000 RPM. Voltage should be 3.3-5.0 volts, and should decrease when engine is tapped with hammer. If voltage reading is as specified, test is complete. If voltage is not as specified, go to step 3).

3) Checking KCU Signal Disconnect KCU connector. Attach jumper wires between KS, VPWR and GND terminals of harness connector and KCU. Start engine. Tap lightly on engine lifting eye bracket with 4-oz. hammer while varying engine speed between 2500 and 4000 RPM. Measure voltage between KC terminal of KCU and ground. If voltage is 3.3-5.0 volts and decreases when engine is tapped, repair KC wire between KCU and ECA. If voltage is not as specified, go to step 4).

4) Checking VPWR At KCU Disconnect KCU connector. Turn key on and measure voltage between VPWR terminal of KCU connector and ground. If voltage is greater than 10.0 volts, go to step 5). If voltage is less than 10.0 volts, go to CIRCUIT TEST VPWR.

5) Checking KCU Ground Circuit Disconnect KCU connector. Turn key on and measure voltage between KC wire of KCU connector and ground. If voltage is more than 10.0 volts, go to step 6). If voltage is less than 10.0 volts, repair KCU GND wire.

6) Checking KS Signal Disconnect KCU connector. Set VOM on AC scale. Turn ignition on. Measure AC voltage between KS terminal of KCU connector and ground. Tap lightly on engine lifting eye bracket with 4-oz. hammer. If voltage is more than .03 volt when engine is tapped with hammer, replace KCU. If voltage is not more than .03 volt, go to step 7).

7) Disconnect knock sensor connector. Set VOM on AC scale. Measure AC voltage between KS terminal of knock sensor connector and ground. Tap lightly on engine lifting eye bracket with 4-oz. hammer. If voltage is more than .03 volt when engine is tapped with hammer, repair KS circuit. If voltage is not more than .03 volt, replace knock sensor.