Diagnosing Volkswagen Idle Quality Problems

Idle quality is challenging to diagnose because it is a vague description at best on most Volkswagens. The textbook definition is an engine speed lower or higher than the specification in the service manual. For drivers, idle “quality” is more difficult to define.

Idle quality could be classified as vibration. However, vibrations can be caused by multiple components, including broken engine mounts. Running conditions that cause misfires can also cause “rough running” or a vibration felt by the driver. Capturing a driver’s complaint and replicating it is critical. Knowing when the idle quality issue occurs is just as crucial of how it feels.

How is idle speed controlled?

Volkswagen fuel injected engines can regulate the idle speed two ways. Some engines have an idle air control or idle stabilization valve. These valves are bypasses around the throttle plate. The flow is controlled by an electric motor. Most late-model Volkswagen throttle by wire systems might not have an idle control system. The angle of the throttle plate is used to control idle speeds. The amount of air allowed to pass for the idling of the engine is typically displayed as a data PID that can be a percentage or angle on a scan tool.

Changing the amount of air means changing the amount of fuel. To create the optimal idle mixture, the engine control module will adjust the open time of the injectors. If the mixture is too rich or too lean, the resulting misfire will create a rough idle.

How is idle speed setting determined?

Idle is not just a number that the engine control module tries to match. The goal of the ECU is to keep the idle speed consistent under changing engine loads from the A/C compressor, alternator and other components. These loads are predictable and anticipated. When an A/C compressor is given the command to engage, the ECM will increase airflow and fuel to the engine. This is usually undetectable by the driver. There are expected loads, and unexpected loads or changes inside the engine that change the idle.

The ECM knows how much suction should be produced by the throttle position data for the engine speed. The amount of air sucked in can change if the pump is not operating correctly. Changes to camshaft timing, restriction in the exhaust or burnt intake valves can change the amount of air required to keep the engine idling smoothly.

The air is measured by a manifold air pressure (MAP)or mass airflow sensor (MAS). A MAP measures negative pressure. A MAS measures the amount of air flowing through intake before the throttle plate. Some engines have both a MAP and MAS.

Some of the greatest idle quality killers are leaks in the intake manifold. To a MAS sensor, the air coming through is unmetered, and the ECU thinks the engine is running too lean so it adds fuel. To a MAP sensor, the leak is seen as a signal the engine is using less air so it takes away fuel. These strategies can result in a change in the quality of the idle. A MAS-only system may have a high idle. A MAP system might stumble and run rough. Modern systems are better at controlling the idle and compensating for the problem, so it will not leave the driver stranded. But, it will still run rough and it will turn on the check engine light.  


Between combustion events, every engine slows down just a tiny amount. If a cylinder is not firing, it slows down even more but still has to speed up when the next cylinder is fired. This makes for a very poor idle. The cylinder can often be isolated using misfire codes or using the misfire counters. 

Courtesy of Brake & Front End.


Volkswagen To Revive Iconic MicroBus In Electronic Form, With ‘Intelligent Co-Pilot’

The Volkswagen MicroBus is making a comeback, and it’s just one of a new generation of VW vehicles that will incorporate artificial intelligence (AI) and deep learning to power self-driving capabilities.

Next-generation VW vehicles will use the Nvidia Drive IX platform “to create new cockpit experiences and improve safety.”

At the kickoff of CES 2018 (formerly known as the Consumer Electronics Show) in Las Vegas , Volkswagen CEO Herbert Diess and Nvidia founder and CEO Jensen Huang discussed on stage how AI is transforming the auto industry. They also highlighted the new I.D. Buzz, Volkswagen’s rebirth of the iconic VW MicroBus, reimagined in electric form and infused with AI technology for the cockpit and self-driving.

“Artificial intelligence is revolutionizing the car,” Diess said. “Autonomous driving, zero-emission mobility and digital networking are virtually impossible without advances in AI and deep learning. Combining the imagination of Volkswagen with Nvidia, the leader in AI technology, enables us to take a big step into the future.”

The Nvidia Drive IX Intelligent Experience platform is a software development kit for creating AI-enabled applications such as facial recognition for automatically unlocking and opening the vehicle, surround perception to alert the driver to potential hazards, gesture recognition for user controls, natural-language understanding for voice control, and gaze tracking for driver distraction alerts.

“In just a few years, every new vehicle will be expected to have AI assistants for voice, gesture and facial recognition as well as augmented reality,” Huang said. “Volkswagen’s work with Nvidia Drive IX technology will make that a reality. Together, we are building a new generation of cars that are safer, more enjoyable to ride in than anything that has come before, and accessible to everyone.”

The VW I.D. Buzz will use Drive IX technology to create “Intelligent Co-Pilot” applications, which will include convenience and assistance systems based on processing sensor data from both inside and outside of the car.

The systems can be enhanced throughout the life of the vehicle via software updates, and can gain new capabilities as further developments are made in autonomous driving. Thanks to deep learning, the car of the future will learn to accurately assess situations and analyze the behavior of others on the road, enabling it to make the right decisions, according to Volkswagen.

The I.D. Buzz is part of the I.D. family with which Volkswagen will launch its electric-car campaign and gradually introduce autonomous driving starting in 2020. The automaker plans to develop more than 20 fully electric vehicle models by 2025.

Article courtesy BodyShop Business.


Volkswagen VR6 Head Gasket Replacement

vw vr6 head gasket cross

The Volkswagen VR6 engine, introduced in 1994, has a narrow “V” configuration that allows six cylinders to be mounted in the same area as a four-cylinder engine. The oddest things about the engine are that the narrow angle between cylinders allows the use of just one cylinder head for the six cylinders, and the timing chain is located between the block and transmission. While head gasket failure is not a common occurrence, it does occur on engines where the cooling system has been neglected due to a lack of regular maintenance. With that said, here are seven tips to make a head gasket job a little easier.

1. Remove and Replace the Cylinder Head Bolts in the Correct Sequence

Since both banks of cylinders have a single cylinder head, they are more prone to distortion. The maximum permissible distortion is 0.10 mm. When removing the head, the sequence starts with removing the outermost bolts on the edge of the head and working your way toward the center. The head bolts can’t be reused because they are torque-to-yield fasteners. To install the head, the bolt sequence starts in the center and then works outward. Refer to the service information for the sequence.

vw vr6 diagram

2. Lock Up the Camshafts First

After the valve cover is removed, the engine should be turned to top dead center and locking plates should be installed on the camshafts. If the chain is off by as little as half a tooth, it can cause driveability problems. If the chain shifts position on the intermediate shaft while the tensioner is out, it can advance or retard the timing of both camshafts. Note: Never turn the engine with the upper chain tensioner removed.

3. Check For Vacuum Line Leaks

Once everything is back together, take the time to inspect for vacuum leaks. On 24-valve engines, the lines that carry vacuum to the EVAP solenoid and canister are the most common areas where leaks can develop. These lines, located on the back of the intake manifold on the passenger side, are made of hard plastic and can crack.

Leaks under the lines’ silver heat-resistant covering can go undetected. If such a leak is not detected, the engine will generate both lean and misfire codes. After a few drive cycles, EVAP codes might be triggered. It is critical that before the vehicle is returned to the customer that the long-term fuel trims and oxygen sensors are checked to make sure the engine is not trending rich or positive.

4. Replace the Guides at the First Sign of Excessive Wear

The upper guides and tensioner should be replaced at the first sign of wear. They can be replaced without removing the transmission. Worn guides are evidence that the driver has been neglecting the oil. If the guides are not replaced, it will cause noise or the engine timing to jump.

5. Soften Gaskets and Then Scrape

When an old gasket is removed, it will leave behind residue on the block and head. It is tempting to go at this residue with an abrasive or metal scraper, but before you ruin the surfaces, use a gasket removal solvent to first soften the residue. It may take 15-20 minutes for the solvent to soften the material, but at that point you might even be able to remove the material with only a shop rag. The use of chemicals will not damage the finish that was applied at the factory.

Note: Never use an abrasive disc or sandpaper. The abrasive materials embedded in the fibers or paper can find their way into the piston rings or crankcase.

vw vr6 torque sequence

6. Leave the Intake and Exhaust Manifolds On

It is possible to gain access to the head gasket without removing the lower intake manifold and exhaust manifold. But, with the total weight of the assembly being more than 60 lbs., you might need help removing it. Be careful resting the head on your bench, as it is possible to damage the combination valve on the bottom of the intake manifold.

7. Check for Cracks

On both types of VR6 engines, cracks can develop between the valve seats and also between the valve seats and spark plug insert. Volkswagen specifies that the crack should not exceed 0.5 mm in width. If the crack is larger than 0.5 mm, you will need to send it to a machine shop to be checked.

Article courtesy ImportCar.


VIDEO: Noise On Braking And Acceleration On VW Vehicles

Andrew Markel shows how control arms can develop a noise during braking and acceleration, and what to replace to fix it. Sponsored by Auto Value and Bumper to Bumper.

Video courtesy ImportCar.


Volkswagen Tech Tip: DTC P0145 Software Update

volkswagen p0145 software update

Models: 2009-‘10 Golf, Jetta and Rabbit models with the 2.5L CBUA engine.

Condition: DTC P0145 (Oxygen Sensor Circuit Bank 1-Sensor 3 Slow Response) is stored in the ECM. No other fault codes are present.

Cause: The monitoring strategy that occurs between the rich-lean phases is too slow.

Correction: Reflash the ECM with the latest software from Volkswagen.

Courtesy of MotoLogic.

Automotive Video

VIDEO: Electronic Parking Brake On Modern Volkswagen Models

Andrew Markel shows how a scan tool can help diagnose and repair the electronic parking brake on modern import vehicles including Volkswagen. Sponsored by Auto Value and Bumper to Bumper.

Video courtesy ImportCar.


Volkswagen Automatic Transmission Fluid Requirements


All models with automatic transmission.

Technical Background

In response to multiple dealership inquires about aftermarket universal (one fluid fits all) automatic transmission fluids and transmission flushing, Volkswagen Group of America, Volkswagen Canada have prepared the following statement.

“At this time, Volkswagen Group of America, Volkswagen Canada do not support or warranty any use of aftermarket universal automatic transmission fluids or the machines used to flush the transmissions. This applies to all standard automatic and DSG transmissions. Due to the functional and design variations in each automatic transmission, the transmission fluid is developed and used by Volkswagen for specific purpose within each application. Under no circumstances are these fluids to be used outside their designated transmission and replacing any of the Volkswagen approved automatic transmission fluids with a universal ‘one fluid fits all’ approach is not accepted.

“Volkswagen Group of America, Volkswagen Canada have not been provided any information from the manufacturers of these aftermarket automatic transmission fluids that indicate that they meet any of the requirements set forth by the developers of these transmissions. There are also no immediate plans to implement these fluids into the currently available automatic transmission fluid selection. As such, any transmission repair where the incorrect fluid is used or the incorrect repair procedure was followed will not be covered under Volkswagen warranty.

“It is also highly recommended that these universal automatic transmission fluids and transmission flushes not be used during customer pay repairs to ensure that the high standards set forth by Volkswagen are always met for the customers, both in and out of warranty.

“Please contact your local FOM/QTM with any further questions or concerns.”

Courtesy of ALLDATA.


Volkswagen: Identifying And Mixing Factory Fill Engine Coolants

G11, green-blue; G12, red; G12+ and G12++, purple; G13 (not pictured), purple.
G11, green-blue; G12, red; G12+ and G12++, purple; G13 (not pictured), purple.


All 1994-2016 (except Routan)

Technical Background

Coolants G11, G12, G12+ and G12++ have been replaced by an improved version. G13 coolant is introduced on all engines.


Identify which coolant the vehicle was filled with from the factory. The photo below shows the color of each type of engine coolant.

Note: The photo above is for color identification only. Your packaging may vary.

The table identifies which coolant can be added to the factory coolant.

Note: G12+, G12++ and G13 coolants are lifetime coolants when used exclusively in the coolant system (not mixed with other coolants).

Coolants can be mixed, as described in the chart, but it is always a best practice to change the coolant due to reduced corrosion protection when coolants are mixed.

Additionally, coolants can be mixed, as described in the chart, when adding/topping off fluid levels. When the coolant is changed due to a cooling system issue, the cooling system should be drained and filled.

VW coolant mixing tableThe table is read by identifying the factory filled coolant at the top and comparing it to the available service coolants to the left. (Example: If the car was factory filled with G12++, the coolant allowed is G12++ or G13.)

Tip: If a vehicle is found to have the incorrect coolant, the cooling system should be drained and then filled with the correct coolant.

Note: Cooling system drain and fill due to coolant mixing or incorrect coolant is not covered by warranty.

Courtesy Import Car.

Automotive Featured

VW Rear Disc Brake Piston Retraction And Pad Replacement

The parking brake mechanism on some VW rear parking brakes can stick due to debris in the arm.
The parking brake mechanism on some VW rear parking brakes can stick due to debris in the arm.

With Volkswagen (VW) rear disc brakes, the parking brake is integrated into the caliper. A ratchet mechanism inside the caliper is supposed to automatically adjust the travel of the caliper to maintain the proper clearance between the pad and rotor. The majority of vehicles you will see at your shop will have cable actuated parking brake mechanisms. Some later models have electronic parking brake mechanisms with motors on the caliper.

In actual operation, the ratchet can sometimes get stuck, frozen or just not work properly, especially after a pad replacement. When replacing the rear pads, you’ll need to turn and compress the piston back into the caliper with care to prevent damage to the ratchet. The best way to do this is with a caliper resetting tool available from many manufacturers. Do not use pliers that could damage the boot.

The caliper pistons turn clockwise to retract, so you’ll need to turn and compress in small steps, being careful not to put too much pressure on the adjusting mechanism. After resetting the caliper piston, pad replacement is the same as the front. The same inspection points are important here as well — the sliders and the pad carrier. On early cars, you’ll need to remove the wheel bearings and races to replace the rotor. Make sure you have seals available, as the factory ones don’t like to come out. When pressing the pistons back into the caliper, I use a bleed bottle connected to the open bleeder to prevent pushing fluid back into the reservoir. Especially on ABS cars, this can prevent problems associated with contamination.

On some VW models, the caliper brackets can cause the brake pads to drag if they are not cleaned and serviced.
On some VW models, the caliper brackets can cause the brake pads to drag if they are not cleaned and serviced.

Pad replacement is the same on all models with rear disc brakes and is accomplished by removing the slide pins and pulling the “knuckle” off of the pad carrier. On later models, the inner pad is clipped to the caliper. The important points to inspect on either design are the caliper slide pins, which should be coated with a high-temperature silicone grease designed for brake use. On cars where the pins are floating in the pad carrier, always remove them, clean and lubricate them and make sure they are free to move throughout their normal range. Also look closely at the surfaces of the pad carrier where they have been wearing on the carrier. Clean this area and lightly file it if the divots are so deep that new pads may get caught during their service life. On some models, there are still thin metal strips that are replaced with the pads to maintain a smooth surface.

Courtesy Import Car.

Automotive Featured

VW & EPA Fiasco Brings Reflashing Into The Spotlight

VW-Logo-1It was revealed VW cheated on EPA emissions tests by programming 2009-2015 diesel vehicles to recognize test conditions the EPA uses. This practice has been going on since the 1990s when sensors gained enough resolution to determine the approximate ambient temperature and transmissions started to share vehicle speed with the engine’s computer.

Most EPA tests do not use the OBDII connector. These tests are performed in a test cell while on a rolling road and are standardized for temperature, time and speed. The VW engineers probably programmed the ECU to look for specific conditions that would only occur in the test cell. If the vehicle detects certain conditions, it engages the “cheat mode” that makes the engine run cleaner.

Cheat Code

The EPA does not have the resources to pull and police the code from the vehicle to look for this cheat code. Just like with most scan tool manufacturers and aftermarket parts manufacturers, the EPA the code is more or less encrypted by its proprietary nature. After this latest revelation, there should be a call for standardized code and language for emissions and engine operation. In a perfect world, this data would be shared with scan tool manufacturers.

Why did VW manufacture its cars this way? To meet the EPA emission levels it probably would have meant a direct impact on the longevity of the engine. The smoking gun is nitric oxide or NOx. The EPA claims the offending VWs in “normal mode” produce NOx emissions up to 40 times higher than acceptable levels. NOx levels are connected to exhaust temperatures. Typically, lower temperature exhaust gases have greater NOx levels, and lower exhaust temperatures may also help to extend the life of the engine and turbo charger. It appears VW took the gamble that if they fudged the EPA tests, they could save money on drivetrain warranty claims. But, when it was announced that the fine could be in excess of $37,000 per car ($18 billion for nearly 500,000 vehicles), VW had to fess up to the deception.

Reflash Recall

EPA and CARB want VW to recall the cars in question so they can be reflashed into compliance to meet mandated emission levels. But I know if I owned one of these vehicles, I would be very hesitant to bring my car to the dealer if it meant that the longevity of the engine could be impacted.

VW is not alone. As stated previously, this EPA emissions test cheat has been around for a long time. It is just VW was caught doing it. Many OEMs have tweaked the engine calibrations for cars in the field to solve problems. GM and Honda have introduced new software to reduce oil consumption on vehicles with cylinder deactivation. The Toyota unintended acceleration recall was partially resolved with a reflash that shut the throttle butterfly if the gas and brake pedal were pushed at the same time.

When the VW story broke, many articles — and even the EPA’s press release — claimed that VW installed a “cheater device.” Many reporters could not believe that vehicle was sophisticated enough that the “cheater device” was nothing more than software.

There is a teachable moment here for shops trying to educate consumers on why vehicle diagnostics with proper scan tools is more important than just swapping parts. It is also a reminder for how reflashing new calibrations can solve problems for vehicles that are out warranty.

Courtesy Underhood Service.