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Old 11-30-2007, 11:56 AM   #20
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Join Date: Nov 2007
Location: Raleigh, NC
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My Ride: 528i 06/00
Originally Posted by ducati000 View Post
Is the M52tu motor the one that is most common with th vanos problem or is it all the e46 bmw's
The vanos in question is part # 11-36-1-440-142. It's found on engines M52TU, M54, M56. These engines are found on most BMW car models:
3-series E46 98-05, 5-series E39 99-03 / E60 & E61 02-05, 7-series E38 98-01 / E65 & E66 02-05, Z3 E36 98-02, Z4 E85 02-05, X3 E83 03-06, X5 E53 00-06

ALL cars with these engines are experiencing the vanos failure.
ALL E46 cars (non M3, non diesel) have one of these engines and this vanos, and therefore ALL are experiencing the vanos failure.

M52TU engines (99-00) were the first with this vanos. They experience the cold weather cold start ideal jolt symptom, which is quite aggravating. This symptom was patched up in the M54 and M56 software.

So, M52TU cars have the most aggravated owners due to the cold morning symptom, but the M54 & M56 engine cars are also experiencing the vanos failure. They will experience a loss of torque and power, particularly in the lower RPM range (< 3K). They might also experience the lower RPM engine hesitations and hiccups.

As you know, owners are also now starting to experience engine fault codes. The fault codes are all related to the vanos exhaust side. The vanos exhaust side cylinder has a powerful spring inserted in it. The spring advances the piston by default to cause advanced exhaust valve timing. This assures no overlap in intake and exhaust valve opening at startup, allowing for a smooth startup. It takes significant oil pressure to oppose the spring and retard the piston. Due to failing (leaking) piston seals the DME becomes unable to retard the exhaust piston. This scenario manifests in the following vanos exhaust side fault codes:
P1520 (BMW 104, 0x68): B (exhaust) Camshaft Position Actuator (faulty reference value).
P1523 (BMW 106, 0x6A): B (exhaust) Camshaft Position Actuator Tight or Jammed (mechanically stuck).
P1397 (BMW 18, 0x12): Camshaft Position Sensor B (exhaust) Circuit.
The Camshaft Position Sensor (CPS) is a common failure. But if replacing the exhaust CPS (w/ OEM CPS) doesn't work then it's likely the vanos failure.

Hope this helps.
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