Valve Lift Control Checksum Error - Signal Implausible

P1350 - 911 Carrera

Valve lift control checksum error - signal implausible

Diagnosis conditions
- Engine idle and acceleration with wide-open throttle

Possible fault cause
- In large lift, a valve stays at small lift, and in small lift, a valve stays at large lift
- In large lift, several valves (different cylinders) stay at small lift, and in small lift, several valves stay at large lift

Diagnosis/troubleshooting

Perform system test for small lift

NOTE: The test is carried out at standstill with the engine running

1 - Select system test.
2 - Select "Request small lift".
If "Valve lift diagnosis not ready" appears, a fault may have been stored. In this case, delete the fault memory.

The engine must be at operating temperature.
1. Increase the engine speed to 2,000 rpm and hold for 30 seconds.
2. Then press the F8 key.
3. Increase the engine speed to 3,000 rpm and hold for 30 seconds.
4. Operate the engine for 30 seconds at engine idle speed.

After 3,000 ignitions the Tester indicates whether a fault is present or not.

In order to ensure that the fault is repaired, the flat-base tappets of the inlet valves of the entire cylinder bank should be replaced if a fault occurs.

Perform system test for large lift

WARNING: Test is carried out while driving. Have a second person operate the Porsche System Tester 2.

1 - Select system test.
2 - Select "Request large lift".
If "Valve lift diagnosis not ready" appears, a fault may have been stored. In this case, delete the fault memory.

The engine must be at operating temperature.
1. Carry out acceleration with wide-open throttle in 2nd gear up to 7,000 rpm. Test in manual range for Tiptronic vehicles.

After 3,000 ignitions the Tester indicates whether a fault is present or not.

In order to ensure that the fault is repaired, the flat-base tappets of the inlet valves of the entire cylinder bank should be replaced if a fault occurs.