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CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - Chris M

I'm getting the fault codes P0106 - MAP/Barometric Pressure Circuit Range/Performance Problem and P2110 - Throttle Actuator Ctl Sys-Forced Limited RPM on my CMax. They only appear when the engine is fully warmed up, until then it drives absolutely normally. First an 'Engine Fault' message appears which is followed by a 'Speed Limited' message. When I pull over and stop, the engine is running roughly and upon switching off, the engine runs on very briefly. The car will restart as normal and run perfectly, although sometimes only for a short distance.

Googling flagged up what I thought may be a couple of potential issues, a split crankcase breather hose or disintigrating swirl flaps. So I removed the inlet manifold to check (all OK) and replaced the MAP sensor as it's cheap and a lot easier to do with the manifold off.

So what next?

Edited by Chris M on 25/01/2016 at 13:59

CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - Chris M

Anyone?

Even the cooking room furniture spammers get a response :-(

CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - elekie&a/c doctor

So what next?well as you have found out you can't fix cars on fault codes alone.Codes are only a "rough Guide" and can lead you completely off in the wrong direction.Also cheap scanners can give bum information with generic non specific vehicle make codes.Perhaps it is time to visit a specialist who understands the working of modern electronic car systems and can interpret the info supplied from a scanner into making an analysis of your engine running issues.

CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - Chris M

Thanks elekie. As you have a habit of giving sound advice, I'll take it.

Finding someone who understands the working of modern electronic car systems and can interpret the info supplied, rather than just replacing expensive components on a car that is worth close to peanuts, may be the first challenge. So far I've only wasted £20 and a couple of hours of my time.

CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - Railroad.
The fault code P0106 - MAP/Barometric pressure and the other code relating to the throttle is your clue. The MAP sensor's job is to tell the ECM inlet manifold pressure. It's actually vacuum, but the ECM doesn't understand vacuum and so it reads negative pressure instead. Barometric pressure (at sea level) is 100 KPa (1Bar or 14.7psi) at engine idle the pressure should be around 40KPa and perfectly steady. The MAP sensor information is essential for the ECM to run the engine correctly. In fact it's the most important component of the system.

If it's reading is erratic it will cause mayhem with the ECM and a substitute value will be placed, and the MIL lamp will illuminate. This will be why the engine appears to run normally, but in fact it's far from normal.

You need to go back to basics. Connect a vacuum gauge to the inlet manifold which in this case will be the most useful piece of equipment in your toolbox. Depending on what the gauge reads will point you to the problem. Google how to use one and what to check for. There could be many things wrong with your engine, and a vacuum gauge will help you to pinpoint it. Even if nothing else it will also tell you if manifold vacuum is normal, in which case you'll need to look elsewhere. Something is definitely wrong though, and that's why these codes were generated. They are both related to the problem.
CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - Chris M

Thanks Railroad. I have had a vacuum gauge connected and get a steady reading of around 23 inHg regardless of engine speed. A quick blip of the throttle results in a dip of 2 or 3 inHg which googling suggests isn't as much as it should be.

CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - Chris M

Those readings in my previous post were taken from the manifold vacuum feed to the swirl flaps and thinking about it, it was the wrong place. I've now retested from just after the throttle body. Reading is 21 inHg dropping to close to zero upon blipping the throttle, jumping to 24 on release and slowly returning to 21. That looks normal I believe?

CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - Railroad.
Yes that's perfectly normal, so it would seem initially you don't have a problem with vacuum leaks, valve timing, loss of compression or sticking valves. The next thing to do is drive the car whilst observing the vacuum gauge. This will test for problems under load. Obviously you will need an assistant to do this safely. Check for vacuum dropping off whilst accelerating which may indicate a restricted exhaust. As I said earlier the MAP sensor tells the ECM inlet manifold pressure. The ECM responds to the information it receives. If no faults are detected using the gauge you will at least know there's nothing wrong with the engine.
CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - 3uga

Use contact spray to clean the MAF. Do that only with the maf disconected and do it somehow as to not need to use the car for a few hours. You need to let the maf dry for some time; not connected to the pcm.

If the maf is foulty you could determine that after you clened it.

I recomend using a second hand maf as a test part.

As for the throtle actuator, you should clean it. The main thing you should know is that your two fault codes are moast likely The result of one problem wich is related to the air intake.

The problem is that not enough freah air is going in you engine. 1 your maf is foulty or dirty and doesent detenct the flow of air. 2 your map sensor is faulty and the cpu doesent know that air is sucked through the intake creating a diference in pressure. 3 your egr valve is faulty or dirty and not closing corectly. The reault is that partial air intake consists of exhaust gases.

Lets say thata the air inntake is 50% air and 50% exhaust gases. In that case the the maf and/of map signals the ecu that only 50% of established intake ia gettin to the engine therefor resulting in limp mode

CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - 3uga

Use contact spray to clean the MAF. Do that only with the maf disconected and do it somehow as to not need to use the car for a few hours. You need to let the maf dry for some time; not connected to the pcm.

If the maf is foulty you could determine that after you clened it.

I recomend using a second hand maf as a test part.

As for the throtle actuator, you should clean it. The main thing you should know is that your two fault codes are moast likely The result of one problem wich is related to the air intake.

The problem is that not enough freah air is going in you engine. 1 your maf is foulty or dirty and doesent detenct the flow of air. 2 your map sensor is faulty and the cpu doesent know that air is sucked through the intake creating a diference in pressure. 3 your egr valve is faulty or dirty and not closing corectly. The reault is that partial air intake consists of exhaust gases.

Lets say thata the air inntake is 50% air and 50% exhaust gases. In that case the the maf and/of map signals the ecu that only 50% of established intake ia gettin to the engine therefor resulting in limp mode

CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - Railroad.
Good response above, but the only flaw is that the OP stated that manifold vacuum measures a steady 21in/hg at idle. That is a good reading. If the EGR valve was stuck open, even only partially, and the exhaust is not restricted in any way then the vacuum reading would be lower than this. The EGR valve should be fully closed at idle but that doesn't mean it's not failing to fully close when driving, which would create a problem. The OP goes on to say that the vacuum reading drops to zero when the throttle is snapped open, and then rises to above 21in/hg when the throttle is closed before returning to 21in/hg again. No faults are therefore indicated. The operation of the idle speed control valve would also show on the vacuum gauge.

I doubt the car has a mass airflow sensor since they'd be no point in having both a MAF and a MAP on a petrol engine. The ECM would not benefit from knowing airflow and manifold vacuum. To know one is perfectly sufficient. It's different on a diesel engine because one measures airflow and the other measures turbo boost pressure, and since a diesel engine doesn't have a throttle valve no manifold vacuum is present.

MAP sensors are easy to test if you have a Mityvac handheld vacuum pump and a voltmeter. There will be three wires on the MAP plug. One is a 5v supply from the ECM. One is earth, and the other is the voltage return to the ECM. Probe the voltage return with your meter red lead with the black lead connected to the negative battery terminal. Switch on the ignition and slowly apply vacuum with the Mityvac onto the MAP sensor. You should see the voltage slowly increase and decrease as you apply vacuum and release it. If the reading is erratic the sensor must be replaced.
CMax 2004 1.8 Petrol - Fault Codes P0106 & P2110 - Chris M

Update.

After a bit of googling, I found a fairly local garage run by “Ford trained senior technicians....with 20 years experience” and using the Ford IDS diagnostics. They diagnosed a failed MAP sensor. I hadn’t told them what I had checked or replaced as I didn’t want them to discount anything based on my word. When they advised me of the failed sensor I told them it had been replaced but they said it wasn’t a genuine Ford item. I knew this, it was a patent part from ECP and I was kicking myself for not using the Bosch alternative at £36. They fitted a genuine Ford one (which is actually Bosch) at £101 (!!) plus diagnostics and a software update, road test and VAT came to £240.

You may be sensing a ‘but’ coming and you would be correct. Five miles down the road, the same fault occurred.

Back the car went for further investigation and the diagnosis was a faulty throttle body. Not repairable they said and only available from Ford at a cost of £450, although they refunded the cost of the sensor and didn’t charge any extra labour. Throttle bodies are available from ECP for £180 (OEM), but I wouldn’t expect a garage to guarantee their work if I was to tell them where to get the parts, even from a reputable supplier.


So, £600 and the car appears to be fixed. Perhaps if I’d known it would be that much i.e. had the diagnosis been correct first time, I wouldn’t have bothered with a repair. But that’s water under the bridge. The bit that grates though is that I was castigated here for simply relying on fault codes when the ‘experts’ went and did the same thing. Mechanics eh!

Edited by Chris M on 05/02/2016 at 16:47