Technical product information
Engine warning light illuminated within the DIP during acceleration - DTC P029900 evident - W12 TSI only
Russische Föderation (5RU),Australia E04 Bentley rest Asia and Australia (6E04),China 796 VW Import Comp. Ltd (Vico), Beijing
(6796),Germany E02 Bentley rest Europe (6E02),Japan E03 Bentley Japan (6E03),Korea, (South) E08 Bentley South Korea
(6E08),United Arab Emirates E06 Bentley Middle East and Africa (6E06),United Kingdom E01 Bentley UK (6E01),United States
E05 Bentley USA and rest America (6E05)
Bentley

Topic
Market
area
Brand

Transaction
2063954/1
No.
Level
EH
Status
Approval
Release
date
Event memory entries
Diagnostic address
0001 - Engine electronics
0011 - Engine Electronics 2
0001 - Engine electronics
0011 - Engine Electronics 2

Event memory entry
Fault type
P029900: Turbo/Super Charger Underboost
P029900: Turbo/Super Charger Underboost
P029900: Turbo/Super Charger Underboost
P029900: Turbo/Super Charger Underboost

Fault status
static
Intermittent
Intermittent
static

New customer code
Object of complaint

Complaint type

information, navigation, communication, entertainment -> symbolic fault indicators -> emission
control system fault indicator
engine -> engine operation -> engine refinement -> engine limp-home mode
engine -> operation, engine control
engine -> engine operation

functionality -> activates

engine -> operation, engine control -> engine control unit
engine -> engine operation -> power development -> engine power

Vehicle data
New Continental GT/GTC - New Flying Spur, Bentayga - W12 TSI
Sales types
Type

MY Brand Designation Engine code Gearbox code Final drive code

3S31BB
3S31BB
3S31BB
3S31BB
3S41BB
3S41BB
3S41BB
4V14A9
4V14A9
4V14A9
4V14A9
4V14A9
4V14G9
4V14G9
ZG21BB
ZG21BB

2018
2019
2020
2021
2019
2020
2021
2017
2018
2019
2020
2021
2020
2021
2020
2021

E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E

Documents
Document name
master.xml

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functionality -> does not end
functionality
functionality
control units, services -> error
message
dimensional accuracy -> too low

Position

Technical product information
Engine warning light illuminated within the DIP during acceleration - DTC P029900 evident - W12 TSI only

Transaction No.: 2063954/1

Customer statement / workshop findings
Customer statement:
Engine warning light and ‘max engine speed 4000 rpm’ warning evident within the DIP during acceleration - Warning on DIP first appears when
accelerating (During boost)
Workshop findings:
•

DTC P029900 evident within the engine control unit/s

Technical background
One of the turbochargers may not be achieving full boost, the issue can be related to a poor connection between the applicable boost pressure
valve vacuum solenoid and the signal wire to the applicable Engine Control Module (ECM) leading to a lack of vacuum supplied to the wastegate when under load
•

In the event the afore mentioned symptoms are evident the operative should refer to the instructions within the Measure section of this
TPI in conjunction with Rep.Gr 21 - Boost pressure valve vacuum solenoid (to assist identifying the component location)

Production change
Not applicable

Measure
When required two operatives are required: x1
operative to drive the vehicle
x1 operative to monitor test equipment
1) Referring to Figure 1 - Monitor the following MWB’s on Bank 1 and 2
•

Normed load value IDE00085

•

Engine RPM IDE00021

•

Air Mass specified/Actual IDE00347/00350

•

Charge air pressure specified actual IDE00190/00191

•

Turbocharger speed sensor 1 IDE03770

•

Intake manifold pressure specified/actual IDE04409/04410

2) Compare the values of each MWB between Bank 1 and 2

Figure 1
3) Referring to Figure 2 - Attach a manual vacuum gauge (B) between the following components: (Depending on the bank which is suspected to

be at fault)
•

Turbocharger wastegate (A) and (C) Boost pressure valve vacuum solenoid

N249 (Bank1)
Or
N547 (Bank 2)
NOTE: Point (D) refers to the engine vacuum system
The manual vacuum gauge must be connected as shown, the hose must be long enough to allow the gauge/readings to be
viewed from inside the cabin

Figure 2
4) The vehicle should be driven whilst the second operative monitors the gauge to confirm if the Boost pressure valve vacuum solenoid is being
actuated in a plausible manner For example: Vacuum supplied to build boost pressure/vacuum supply closed when the target
boost pressure is achieved
If vacuum supply to the wastegate is not plausible the operative must check the vacuum supply to the Boost pressure valve
vacuum solenoid
5) Carry out a wiring integrity check between the applicable ECM and the applicable solenoid circuit - Refer to the applicable Rep.Gr wiring
diagram
•

Figure 3 shows a location which should also be checked for damage/kinks NOTE: The disconnected pin is shown for photographic
purposes only

Figure 3
7) In the event an issue is suspected, for test purposes the operative should overlay the suspected wiring as follows:
•

Make and temporarily fit an overlay wire between the applicable boost pressure valve vacuum solenoid and the signal wire to the

applicable Engine Control Module (ECM)
•

Attempt to erase the DTC and carry out a road test to confirm the issue has been successfully diagnosed

The overlay MUST not be left in place under any circumstances, the operative should repair the wiring as per Rep.Gr 97

Warranty accounting instructions
Diagnosis time
Warranty type
110 or 910
Labour operation code
97 09 01 00
Damage service number 97 09
Damage code
00 26
Time
Must not exceed 120 TU
Road test
Labour operation code 01 21 00 00
Time
50 TU