Check Engine Light - Illuminated

Boxster

1/98

03..

0

Binder - 0, Entire Vehicle

04-02-98

"Check Engine" Light On

Vehicle Type:
Boxster

Model Year:
As of 1997 (V)

Concern:

Illumination of the "check engine" light.

Information:

The following are three possible conditions which may cause the check engine light to illuminate. These areas of mechanical faults can result in misfiring, and the subsequent storing of misfire detection faults in the DME fault memory.

Procedure:

Clear the working log of the PST2 and read out the fault memory. Save all new information to the working log with the F4 key. Print the new OBD working log before beginning repairs. Submit an OBD II report to Porsche Cars North America Technical Services, and attach the working log print out. Please include the corrective action sheet with a brief explanation of the complaint, cause, and the present status of the repair. Use the information from the PST2 to determine if any of the following conditions exist.

Condition:

1. Dirt in the valve tappets.

Periods of valve tappet noise in conjunction with an illuminated check engine light may indicate dirt in the valve tappets. In this case, the DME records misfiring (usually as sporadic faults) in the fault memory of one or more cylinders. Also, the adaption values for TRA/TRA2 and FRA/TRA2 appear to be normal. Normal mean adaption values:

TRA/TRA2 mean value = 0.00
FRA/FRA2 mean value = 0.98 - 1.03

Correction:

- Remove all valve tappets with the engine installed. Refer to section 15 59 20 of the Boxster Technical Manual, Binder: Group 1 - Engine, pages 15-57 - 15-75 for work procedure.

- Remove the valve tappet guide assembly and check for damage or excessive irregularities. See section 15 59 02 of the Boxster Technical Manual, Binder: Group 1 - Engine, page 15-49 for permissible irregularities. Clean all oil passages and dry with compressed air.

- Replace all valve lifters.

- Perform a test drive and check for valve tappet noise.

Labor Operation Time Units Description

15 05 20 06 960 Remove and install camshafts, 2 sides

15 05 20 1050 Remove and install camshafts, 2 sides, air conditioning

15 59 20 84 60 Remove and install 24 lifters

15 43 20 50 50 Remove and install 2 lifter bores

Condition:

2. Camshaft Timing not in Specification.

In this case, the fault memory indicates misfiring of a complete cylinder bank, with no indication of valve tappet noise. The idle speed adaption values (TRA/TRA2) of bank 1 (cylinders 1 - 3) and bank 2 (cylinders 4 - 6) differ by a significant amount. Generally, the adaption values for FRA/FRA2 will be normal, and near the mean value of 0.98 - 1.03.

Correction:

- Adjust the camshaft timing. Refer to sections 15 05 06 and 15 59 20 of the Boxster Technical Manual, Binder: Group 1-Engine, pages 15-20 - 15-39 for work procedure.

- Perform a test drive. The adaption values must be normal.

Labor Operation Time Units Description

15 05 20 06 100 Camshaft adjusted, 1 side

15 05 16 50 180 Camshaft adjusted, 2 sides

Condition:

3. VarioCam Actuation.

VarioCam actuator mechanically faulty.

In this case, the VarioCam actuator does not fully switch over from power valve timing to torque valve timing. The fault memory records misfiring of a complete cylinder bank in the range of 1200 - 1500 rpm. The recorded adaption values for TRA/TRA2 and FRA/FRA2 are normal.

Correction:

- VarioCam actuator faulty, replace VarioCam actuator. Refer to sections 15 05 33 and 15 59 20 of the Boxster Technical Manual, Binder: Group 1-Engine, pages 15-21 - 15-45 for work procedure.

Literature:

Manual-On-Board Diagnostic Troubleshooting (0DB II), Boxster