Knock Control Test Pulse - Signal Implausible

P1386

Knock Control Test Pulse - Signal Implausible

Function
The knock control system is designed to detect knocking combustion and to retard the ignition timing for the knocking cylinder(s). When no further knocking occurs, the ignition timing is advanced again gradually to the specified value. Because of the engine design (opposed-cylinder engine), two knock sensors are needed.

Knock sensor 1 - cylinders 1 to 3
Knock sensor 2 - cylinders 4 to 6

Diagnosis conditions
- Engine speed [>] 3600 rpm.

P1384-P1386:

Wiring Diagram







Diagnosis Procedure

DTC's P1384 and P1385







DTC P1386







1 Check wiring from DME control module to knock sensors for continuity.

1. Remove knock sensor connectors.
2. Connect special tool 9616 to wiring harness (DME control module connector).
3. Connect ohmmeter to special tool 9616, pin 13, and to knock sensor 1 connector, pin 1.
Display: 0 - 5 ohms

4. Connect ohmmeter to special tool 9616, pin 41, and to knock sensor 2 connector, pin 1.
Display: 0 - 5 ohms

5. Connect ohmmeter to special tool 9616, pin 71, and to knock sensor 1 connector, pin 2.
Display: 0 - 5 ohms

6. Connect ohmmeter to special tool 9616, pin 71, and to knock sensor 2 connector, pin 2.
Display: 0 - 5 ohms

If a resistance of Infinity ohm is displayed for points 3 to 6, check wiring harness for chafing and pinching damage.

2 Check wiring from DME control module to knock sensors for short to ground.

1. Remove knock sensor connectors.
2. Connect special tool 9616 to wiring harness (DME control module connector).
3. Connect ohmmeter to special tool 9616, pin 13, and ground.
Display: Infinity ohm

4. Connect ohmmeter to special tool 9616, pin 41, and ground.
Display: Infinity ohm

If a resistance of 0 - 5 ohms is displayed for points 3 and 4, check wiring harness for chafing and pinching damage.

3 Check wiring from DME control module to knock sensors for short to B+.

1. Remove knock sensor connectors.
2. Connect special tool 9616 to wiring harness (DME control module connector).
3. Connect voltmeter to special tool 9616, pin 13, and ground.
Display: 0 V

4. Connect voltmeter to special tool 9616, pin 41, and ground.
Display: 0 V

5. Connect voltmeter to special tool 9616, pin 71, and ground.
Display: 0 V

If battery voltage is displayed for points 3 to 5, check wiring harness for chafing and pinching damage.