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When you step on the brakes to slow down downhill, the car may shake jerkly or cause an unnatural deceleration that pulls you forward.
There is no problem on flat ground, but only the deceleration on the slope is jerky – this is a relatively common consultation at VW.
The cause is not only the brakes, but also multiple such as DSG control, engine braking method, mount deterioration, and air intake control. If left unattended, it will be difficult to control on long downhill slopes and it will be dangerous.
In this article, we will summarize the causes of “jerky deceleration” on downhill slopes in an easy-to-understand manner by structure.
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Shock occurs when starting and decelerating
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- Common symptoms
- There are four main causes.
- Cause (1) 😀 SG deceleration control is disturbed (most common)
- Cause (2): Initial braking of the brake is too strong (pad characteristics)
- Cause (3): Engine and mission mount deterioration (cannot absorb shaking)
- Cause (4): Disturbance of intake control (throttle closing side is unstable)
- Points that can be checked in DIY
- Is it okay to drive? (Urgency)
- Approximate repair cost
- Related parts to check at the same time
- Conclusion
- Defect details by vehicle type
- Frequently Asked Questions (FAQs)
Common symptoms
- The brakes jerk only on downhill
- Engine braking suddenly feels strong
- Even if you weaken the brakes, it shakes
- It doesn’t bother me on flat ground
- Especially at low speeds
- Switching between D→R and other devices can also cause a slight shock.
There are four main causes.
- Disturbance of DSG deceleration control (downshift).
- Brake pads brake initial braking too strong/uneven
- Deterioration of engine and transmission mounts (amplification of shaking)
- Disturbance of intake control (control instability on the closed side of the throttle)
Cause (1) 😀 SG deceleration control is disturbed (most common)
When does it happen?
- Engine braking suddenly and strongly on a downhill slope
- When you step on the brake lightly, it “clicks”
- Shakes in 2nd →1st gear downshift
Why do I have that symptom?
DSG is
- Downshift
- Disconnect/connect the clutch
- Adjusting the engine brake
at the same time. If this is disturbed,
the jerking will be emphasized by the load change unique to the downhill.
Especially in the dry DQ200,
- Downshift is sudden
- Clutch connection is rough
- Engine brake suddenly rises
It is easy to behave like this.
If left unattended?
- Jerky deterioration
- Progression to clutch wear
- It becomes difficult to adjust the speed on mountain roads, etc.
Cause (2): Initial braking of the brake is too strong (pad characteristics)
When does it happen?
- It works hard at the beginning of the step
- Especially on the way down.
- Symptoms began to appear after changing the pads
Why do I have that symptom?
On downhill slopes, the weight transfer is biased forward.
In that state, if the “pad has strong initial braking”,
- Braking force suddenly rises
- Compatibility with the front load increases nose dive
→ Leads to jerky deceleration.
At low speeds, the behavior is particularly large.
If left unattended?
- Increased tire wear
- It fades with a long descent
Cause (3): Engine and mission mount deterioration (cannot absorb shaking)
When does it happen?
- When decelerating, the car body sinks forward greatly
- Doesn’t stop smoothly
- Large shaking even when switching between D/R
Why do I have that symptom?
If the mount is weakened, it will not be able to absorb the sway of the load transfer, and
the back-and-forth sway just before the stop will be amplified.
When going downhill, the front load naturally increases, so
the “shaking” of mount deterioration is likely to occur noticeably.
If left unattended?
- Worsening shock when stopping and starting
- Other Mount Damage Risks
- Deterioration with brake control
Cause (4): Disturbance of intake control (throttle closing side is unstable)
When does it happen?
- Rotation drops too much when the accelerator is off.
- Shaking when decelerating with air conditioning on
- Jerking with low-speed accelerator on/off
Why do I have that symptom?
On downhill slopes, there are more situations where the engine brake is used with the accelerator off.
At this time, if the throttle does not close/open too smoothly,
- Engine braking suddenly comes out strongly
- Shaking without matching the brake pedaling force
- Rotation drops increase
It is easy to get an “unnatural deceleration”.
If left unattended?
- Slow jerking worsens
- Increased stagger at launch
So there are three options
In such a case, there are three realistic options for VW owners:
(1) First, a mechanic who is strong in diagnosis and estimation of
imported cars will identify the cause and propose the minimum necessary.
▶ Find a VW repair shop (buv.LABO)
(2) Foreign car specialty for appraisal
maintenance history and external parts plus assessment before high-cost repairs.
▶ Free appraisal with foreign car baton
(3) “New car at a fixed price” to avoid repair cost risk Relieve
yourself from breakdown stress with a monthly fee including vehicle inspection, tax, and maintenance.
One point
Even if you think it’s okay because you can run, you’re actually holding a bomb that you don’t know when it will explode.
The sooner you move, the less cost and damage you will have.
Points that can be checked in DIY
- Downhill only swaying → DSG control or brake initial braking
- Idling up and down → Intake and throttle
- D/R switching also shakes greatly → mount
- Occurs after pad replacement → possible pad characteristics
- Worse with air conditioning on → Intake control
*The final decision will be made at the maintenance shop.
Is it okay to drive? (Urgency)
- Light jerk only: Allowed to run
- Strong shaking on the descent: medium (early inspection)
- Unstable braking and abnormal noise: High
- DSG warning light on: Very high (no running)
When a driving problem occurs, it may be necessary to tow the truck depending on the situation.
In these cases, it may be covered by road assistance or riders of automobile insurance, so it is safe to lightly review the contents of your current contract.
If you may not have a proper understanding of the coverage, you can use a comparison service to check the coverage details and premiums of multiple companies at once. Since you can get a complete picture in a short time, many people use it for repairs and inspections.
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Approximate repair cost
| Work Description | Approximate cost |
|---|---|
| DSG Learning Value Reset | 5,000 to 15,000 yen |
| Brake pad replacement | 15,000 to 30,000 yen |
| Engine/Mission Mount Replacement | 20,000 to 50,000 yen |
| Throttle Cleaning | 5,000 to 15,000 yen |
| Intake air leak inspection | 5,000 to 10,000 yen |
You can scroll
*Early inspection will ultimately reduce costs.
👉Summary of maintenance and custom costs & working days of VW specialty store Nile Plus
Related parts to check at the same time
- DSG Clutch Actuation Values
- Brake pads and rotors
- Engine/Mission Mounts
- Throttle Valve Air Flow
- Lower Arm Bushing
- Idle Control Value
▼List of individual pages about engine and drive system repair and maintenance▼
Conclusion
The symptoms of jerking when decelerating downhill are mainly caused by DSG deceleration control, braking initial braking strength, mount deterioration, and disturbance of intake control. Downhill is a point where the front load increases, so even a small problem is likely to appear as a behavior disorder.
For safety, early inspection is recommended.
Even if the symptoms are similar, the causes vary from vehicle to vehicle.
Even if it is the same “downhill jerky”, there are various causes such as DSG, brake mounts, and intake control.
If you are unsure, it is safe to have it inspected at a maintenance shop without overdoing it.
Defect details by vehicle type
Although the “way of getting out” the defect is similar, “which model has many problems” is slightly different for each car model.
Trends by vehicle model and common breakdown cases among other owners are summarized on the following page.
Frequently Asked Questions (FAQs)
Q1. Is it a malfunction to jerk just downhill?
A1. It is often a harbinger of a breakdown. In particular, if the DSG deceleration control is disturbed, the initial braking strength of the brakes, the mount deterioration, and the instability of the intake control overlap, “symptoms may only appear on hills”. It is recommended to inspect it as it will get worse if left untreated.
Q2. Is there a possibility of improving it with a DSG learning value reset?
A2. It is. The dry DQ200 and other models have severe downshift control when decelerating, so there are cases where jerks become stronger due to deviations in the learning values. However, if the root cause is clutch wear or mount deterioration, resetting alone will not improve it.
Q3. Can brake pads cause stiffness?
A3. It is. If you are wearing pads with strong initial braking, you will slow down sharply when you are downhill when you are loaded in front of you. If you start to worry about it after replacing the pads, it is highly likely.
Q4. Is the downhill jerk dangerous? Is it okay to drive?
A4. If it is mild, it can be driven, but if it shakes strongly, the engine brake rises suddenly, or it is accompanied by abnormal noise, it is a highly dangerous situation. It is especially difficult to control on long downhill slopes, so it is safe to inspect early.
Q5. Are there any checkpoints that can be determined by DIY?
A5. It is. It can be easily isolated: → DSG control or brake characteristics, worsening after pad replacement → pad characteristics, symptoms intensify when the air conditioner is turned on → Intake control, impact → mount for D/R switching. However, the final decision is certain to be made by the maintenance shop.
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