Emissions - MIL ON/Codes 81 and 81 in DME Memory: Overview

SI B11 05 04
Engine

March 2008
Technical Service

This Service Information bulletin supersedes S.I. B11 05 04 dated July 2006.

[NEW] designates changes to this revision

SUBJECT
M62TU/S62 Secondary Air Diagnostics and Air Delivery Passage Cleaning Procedure

MODEL
E38 (7 Series), E39 (5 Series), E53 (X5) and Z8 with the M62TU or S62 Engine

SITUATION

When accumulated vehicle usage exceeds 35,000 miles, a small number of vehicles listed may experience illumination of the Check Engine Light and the setting of the secondary air system fault codes 80 and 81 in [1][2]DME memory.

CAUSE

If all relevant components (air pump, one way valve, solenoid valve etc.) are determined to be functioning properly and the condition still exists, the cause may be clogged secondary air delivery passages within the cylinder heads.

Excessive combustion chamber/exhaust manifold deposits may be attributed to usage of fuels with inadequate level of detergents. BMW recommends exclusive use TOP TIER Gasoline to prevent an excessive deposit build-up.

CORRECTION








A tool kit has been developed that will remove the guesswork in the diagnosis of clogged secondary air passages and provide a method to remove the built-up carbon deposits which are causing the fault. This tool has already been distributed to all centers via the Automatic Tool Shipment Program. Additional cleaning kits, Part Number 99 00 0 006 668, may be purchased through your PDC. Refer to Parts Information bulletin 01 01 95 for tool warranty details.

[NEW] NOTE:

Main secondary air passages core plugs (12 mm) are not included in the latest production kits. Core plugs (PN11 12 1 736 330) have to be ordered separately from PDCs (Qty: 3 per vehicle). Replacement reamers and sets of brushes are available under the following part numbers:

^ Reamer 4mm PN 83 30 0 444 759

^ Nylon Clean-up brushes PN 82 11 0 416 754 (set of 12)

^ Brass brushes PN 82 11 0 416 755 (set of 3) of 3)

PROCEDURE

In cases where the check engine light is on and fault code 80, 81 (or both) are stored in [1][2]DME memory, it is necessary to first verify that all external secondary air components are functioning. After following the applicable test plan in DISplus, proceed with the calibration of the cylinder head back pressure tool.





Lift red regulator knob (1) and unscrew counterclockwise until the stop is reached.





Insert plug (1) into end of tube (2) and tighten T handle until plug is secure.

Attach pressure transducer (2) from DISplus to fitting on tool.





Set DISplus to "Measuring Systems" and "Pressure Bar". The approximate 1 bar reading on the screen is the ambient atmospheric pressure.





Connect shop air (1) and open the yellow flow control valve (2). Turn red regulator knob (3) clockwise.





Rotate until 3.5 bar is registered on the screen. Lock by pressing down on the regulator knob.

Shut off yellow flow control valve, disconnect pressure transducer and remove the plug from end of the pipe.

Testing procedure

Please note that pictures of the engine are for clarity purposes only. At no time during the procedure is the engine removed from the vehicle.

Remove fan assembly. Refer to Repair Instruction 11 52 020 in WebTIS.

Remove the two 10 mm bolts (2) securing the delivery tube (3) to the cylinder heads at position indicated (1).





Position tubing out of the way so that there is access to the ports in the heads.





Insert tool (1) in right cylinder head (1-4) secondary air supply passage (2). Connect pressure transducer from DISplus (3) to tool, connect shop air and open yellow flow control valve to allow the free flow of regulated air to pass through the head. Observe backpressure reading on DISplus. Readings in excess of 1.10 bar indicate restrictions within the head that require cylinder head removal. Repeat test for left side head.

Note:
Prior to engine disassembly, perform a thorough engine compression and leakdown test to ensure that there are no engine problems that could cause a short term reoccurrence of the problem.





Parts Information








WARRANTY INFORMATION

Covered under the terms of the BMW New Vehicle Limited Warranty.





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