Checking CMP sensor Ground connection

Connect multimeter US 1119 (Fluke 83 or equivalent) and check resistance between C sensor connector terminal 3 and engine Ground.
Specified value: Continuity

If there is not continuity, and the LED does not flash:

Replace CMP sensor.
Check readiness code. See READINESS CODE, CHECKING . If Diagnostic Trouble Code (DTC) memory has been erased, then generate new readiness code. See READINESS CODE, GENERATING .

If one of the specified values was not obtained:

Connect VAG1598/19 test box to Engine Control Module (ECM) harness connector. See VAG1598/19 TEST BOX, CONNECTING .

Fig 1: Identifying Knock Sensor Harness Connector Terminals

Check wiring for open circuit, short circuit to B+ or short to Ground between CMP sensor and ECM.

KNOCK SENSOR CIRCUIT TEST

CMP sensor connector terminal	VAG1598/19SOC (ECM terminal]
1	A3 (+5 volts)
2	B2 (signal)
3	D12 (Ground)

Fig 2: Identifying ECM Connectors

If, after erasing Diagnostic Trouble Code (DTC memory, CMP sensor malfunctions are still stored and all test results to this point have been OK:

Remove CMP sensor.
Make sure that trigger wheel is correctly installed.
(Can be damaged if mounting bolts are incorrectly torqued).

If CMP sensor trigger wheel is OK: