audi A4 2.0tdi CAGA intermittent non start

Ask for and share advice on using the PicoScope kit to fix vehicles here.
Post Reply
aronfields
Newbie
Posts: 2
Joined: Thu Apr 18, 2019 8:08 am

audi A4 2.0tdi CAGA intermittent non start

Post by aronfields »

At the minute i have a 2008 A4 2.0 tdi CAGA engine in the workshop. Customers complaint has been of intermittent non start issues. Starts perfectly from cold every day, typical scenario is car driven home from work 20+ mile journey customer goes into the house for 15-20 mins comes back out car will not start turning over perfect just no start. leave the car for 5 minutes and car will start perfectly.

this has been and on going issue over the last 5-6 months.

at the minute its showing only 1 fault code for engine mount solenoid

starters been replaced ,battery's been replaced,

at the time i could not get the car to replicate the fault

in between visits to our garage the car was at a indie VAG specialist im not sure what he actually replaced or did.

then at the customers request we had a warm start remap carried out, after the remap the ecu showed the following faults codes

4901 enigine mount solenoid
5199 relay for fuel pump 2 (j49) short to ground
7859 intake manifold flap position sensor bank 1mechanical failure

the guy who did the remap surmised that these codes had previously been deleted from the ecu as prior to the warm start map the car showed on the 4901 fault code

so again he deleted them from the ecu........

when i eventually got the car to replicated the fault in the workshop with the snap on scanner i checked both crank and cam sensor reading and both matched perfectly however the car started after around a minute of cranking.

the fault code for the fuel pump relay 2 seems very strange and i cannot seem to find any info at all online for this fault code.
has anyone come across this before ?????



any help much appreciated

User avatar
vasek
TwoWaves
TwoWaves
Posts: 106
Joined: Tue Feb 17, 2015 7:27 pm

Re: audi A4 2.0tdi CAGA intermittent non start

Post by vasek »

Just a guess.
The car with the CAGB engine has two pumps.
Supplementary pump V393, and pressurisation pump G6.
If the firmware does not correspond to the CAGA variant,there will be a static error on the relay of the second pump.
.
You should pay attention to the amount of pressure when scrolling the starter.
Here is a serviceable start CAGB.
The voltage on the pressure sensor is about 1.0 volts.
The operating time of the starter is 600 ms:
Attachments
AUDI A4 2.0 CAGB START T= 600 ms.PNG

Post Reply