Mercedes M272/M273 Balance Shaft & P0016/P0017 Timing Chain Guide

November 10, 2026

Mercedes M272 M273 timing chain tool kit in case

If you own a mid-2000s Mercedes with the M272 V6 or M273 V8 and the check engine light keeps coming back with P0016 or P0017, there's a good chance you're looking at the most expensive known problem these engines have. Early M272 engines wear the teeth off the balance shaft sprocket, and early M273 V8s wear the timing chain idler gear. Either way, the right-bank camshafts drift out of time with the crank. This guide covers the affected engine ranges, diagnosis, the repair and the tools.

Signs of a Worn Balance Shaft Sprocket or Idler Gear

Check engine light with P0016 and/or P0017 (Mercedes codes 1200 and 1208), crank/cam position correlation faults
The codes come straight back after they're cleared and the engine is restarted
Rough or uneven idle, hesitation, and occasional misfires as the timing error grows
Harder starting and, in bad cases, rattle from the front of the engine or the engine stalling

The light often comes on long before the engine runs badly. Don't ignore it: the wear continues, and these are interference engines.

The same codes can also come from a failed camshaft position sensor, a sticking camshaft adjuster or solenoid, low oil pressure, or a stretched chain. That's why diagnosis matters before anyone quotes you for an engine-out repair.

Which Engines Are Affected

The M272 V6 and M273 V8 were used across most of the Mercedes range from about 2004 to 2011: C, E, CLK, CLS, SLK, SL, S, R, ML and GL models badged 280, 300, 350, 450, 500 and 550, plus some Sprinters. Only early engines are at risk. Mercedes changed the sprocket and idler gear material during 2006, and service bulletin LI03.30-P-050027 gives these cutoffs:

M272 V6 (balance shaft sprocket): engine serial numbers before 2729..30 468993
M273 V8 (chain idler gear): engine serial numbers before 2739..30 088611

Only the last eight digits matter. For example, an M272 numbered 30 376901 falls inside the range and 30 539056 doesn't. You can get your engine number from a dealer using your VIN, or from a VIN decoder. Don't go by the trunk badge. Check the engine code and full serial number, because a car built in 2007 may still have an early engine.

Mercedes never issued a recall. A US class-action settlement offered partial reimbursement for a time, but its claim deadlines and coverage periods have expired.

How the Problem Is Confirmed

A sound diagnosis goes in this order:

Read and record the codes with a Mercedes-capable scan tool, and save the freeze-frame data before clearing anything.
Clear and restart. If 1200/1208 come back immediately, suspect mechanical wear rather than an electrical fault.
Check the cam timing. With the camshaft Hall sensors removed and the crank turned to the mark given in the service information, the stamped marks on each impulse wheel should be centered in the sensor openings. On these engines the error usually shows up on the right bank only.
Look at the gear. A flexible borescope through the right-hand timing case or camshaft adjuster cover lets you see the balance shaft sprocket (M272) or idler gear (M273). Worn, pointed or missing teeth confirm the diagnosis.

Parts for the Repair

If the gear is worn, the fix is to replace the worn part and the timing components it has been chewing on:

M272: balance shaft with the revised sprocket. The sprocket isn't sold separately, so the whole shaft is replaced.
M273: timing chain idler gear
Timing chain, chain guide rails and the chain tensioner
Camshaft adjustment solenoids (the bulletin calls for them)
Gaskets and seals for everything you open, plus engine oil and a filter. The bulletin calls for oil and filter changes after the repair.

Mercedes sells complete repair kits, and the bulletin lists the part numbers. Order by VIN. Part numbers for the tensioner and gears have been superseded several times, so don't copy a number off a forum post.

Tools You'll Need

Timing Chain Tool Kit for Mercedes M112/M113/M272/M273: locks the flywheel and camshafts so nothing moves while the chain is off. It comes in a labeled case.

Flywheel Locking Tool for Mercedes M112/M113/M272/M273/M276 (OE 112589034000): holds the flexplate when you break loose the crank bolt or flexplate bolts. It's useful if you want a dedicated plate lock on the engine stand.

An adjustable torque wrench in 3/8" and 1/2" drive. The cam adjuster bolts, tensioner and crank bolt all have specific torque values.
A Mercedes-capable scan tool and a flexible borescope for diagnosis
Engine hoist, engine stand and transmission support for the engine-out repair
Standard metric and Torx/E-Torx sockets

The kit does not include a chain breaker or riveting tool. Browse the rest of our Mercedes-Benz V6 & V8 tools.

The Job, Step by Step

This is an overview of a big job, not a substitute for the factory procedure. Shops quote it at well over 20 labor hours. Because the balance shaft sits inside the block (and the M273 idler gear sits deep in the chain drive), the repair is normally done with the engine removed.

Confirm the diagnosis first. Check the engine serial number, do the cam timing check, and look with the borescope. Don't pull an engine on codes alone.
Remove the engine. Most of the front of the car comes apart, and the A/C system has to be recovered first. Mount the engine on a stand.
Set the engine to its timing position and lock it. Turn the crank clockwise only, to the position given in the service information. Fit the flywheel lock and camshaft locking tools from the kit before you remove anything that holds chain tension.
Remove the covers. This means the cam sensors, camshaft adjuster covers, oil pan and front timing cover, then the tensioner, camshaft adjusters, guides and chain.
Replace the worn gear. On the M272, remove the old balance shaft and fit the new one with the revised sprocket. On the M273, replace the idler gear. Inspect the oil pump drive and the sprockets you're keeping. Replace any sprocket that's worn along with the chain.
Install the new chain, guides and tensioner with the cams locked and the timing marks aligned. Torque the camshaft adjuster bolts and everything else to factory spec.
Remove the locking tools and turn the engine by hand, clockwise, through two full turns. Recheck that the impulse wheel marks are centered. If anything binds, stop and find out why.
Reassemble and refit the engine, then change the oil and filter, clear the codes and confirm the cam positions with a scan tool.

Common Mistakes

Replacing parts on codes alone. Cam sensors and adjuster solenoids cause the same codes for far less money. Measure the timing and look at the gear first.
Turning the engine backwards. Counterclockwise rotation can collapse the tensioner, break a guide or jump the chain.
Fixing the gear but keeping the old chain and tensioner. A worn chain will be noisy again before long, and the engine has to come out again to fix it.
Skipping the oil change afterward. Metal from the worn gear circulates through the adjusters and solenoids.
Trusting a "late build" date. Check the engine serial number, not the model year.

Frequently Asked Questions

Do P0016 and P0017 always mean a bad balance shaft on the M272?

No. P0016 and P0017 (Mercedes 1200 and 1208) only say the cam and crank positions disagree. A failed camshaft position sensor, a sticking adjuster or solenoid, low oil pressure or a stretched chain can set them too. On an early M272 or M273, codes that return immediately after clearing, plus a timing check and a borescope inspection showing worn teeth, confirm the worn gear.

How do I know if my M272 or M273 is in the affected range?

Check the engine serial number, not the model year. Mercedes bulletin LI03.30-P-050027 lists M272 engines before 2729..30 468993 and M273 engines before 2739..30 088611. Only the last eight digits matter. A dealer can look up the engine number from your VIN, or you can use a VIN decoder. Later engines received a harder sprocket and idler gear material.

Can the M272 balance shaft be replaced with the engine in the car?

Normally, no. The balance shaft sits inside the block and the M273 idler gear sits deep in the chain drive, so the repair is done with the engine removed. Shops quote well over 20 labor hours. The borescope inspection can be done in the car through the right-hand cover, so you can confirm the problem before committing to the job.

What tools do I need for M272/M273 timing chain work?

You need flywheel and camshaft locking tools to hold the engine in time while the chain is off, a torque wrench for the adjuster and crank bolts, a Mercedes-capable scan tool, and a borescope for diagnosis. The Wrench Haus M112/M113/M272/M273 timing chain tool kit covers the locking side. For the engine-out repair you also need a hoist and an engine stand.