DB9 electrical woes (cross-post)
#1
06-11-2016, 06:29 PM
DB9 electrical woes (cross-post)
I have a 2006 DB9 Volante (US version) and I was out today for a run to the shops in fairly hot weather (around 90F/32C). I had the top down.
The car ran fine on the outbound trip, although I thought I noticed a slight but unusual hesitation/stutter in the idle at traffic lights. After half an hour shopping, I restarted the car and began to head home, about a 20 minute drive. Almost immediately I heard a couple of "bongs" and noticed that the ABS warning light came on. Then the speedometer (both analogue and digital) and tachometer stopped working. The turn signals also failed.
When I arrived home, the convertible roof would not operate and I noted that my right turn signal was flashing (independently of the control stalk). When I turned the ignition off the turn signal stopped, but the nav screen stayed open and displayed my position. Also, the boot would not open with either the key fob or the external electric button.
This happened once last year, also on a hot day, but I replaced the battery and I didn't have the problem again. I assumed that the old battery was failing and released the gremlins. My current battery, however, is in good shape and I keep the car connected to a CTEK tender every night.
As the continued nav screen operation indicates that there is still current being drawn, I worried that the battery might discharge. Because I can't open the boot, I wired clips to the CTEK and connected it to the positive terminal and a ground under the bonnet. The CTEK shows the battery to be in good shape and taking a charge.
So...any suggestions?
Thanks!
The car ran fine on the outbound trip, although I thought I noticed a slight but unusual hesitation/stutter in the idle at traffic lights. After half an hour shopping, I restarted the car and began to head home, about a 20 minute drive. Almost immediately I heard a couple of "bongs" and noticed that the ABS warning light came on. Then the speedometer (both analogue and digital) and tachometer stopped working. The turn signals also failed.
When I arrived home, the convertible roof would not operate and I noted that my right turn signal was flashing (independently of the control stalk). When I turned the ignition off the turn signal stopped, but the nav screen stayed open and displayed my position. Also, the boot would not open with either the key fob or the external electric button.
This happened once last year, also on a hot day, but I replaced the battery and I didn't have the problem again. I assumed that the old battery was failing and released the gremlins. My current battery, however, is in good shape and I keep the car connected to a CTEK tender every night.
As the continued nav screen operation indicates that there is still current being drawn, I worried that the battery might discharge. Because I can't open the boot, I wired clips to the CTEK and connected it to the positive terminal and a ground under the bonnet. The CTEK shows the battery to be in good shape and taking a charge.
So...any suggestions?
Thanks!
Last edited by zuman; 06-11-2016 at 08:01 PM. Reason: Update
#2
06-11-2016, 08:26 PM
Registered User
Join Date: Oct 2014
Location: Northeastern Pennsylvania, USA
Posts: 138
Rep Power: 17 
You may have a throttle pedal failure... This happened to my 05 DB9 Manual and the fault codes present were:
P2105, Throttle Actuator Control System - Forced Engine Shutdown
P2106, Throttle Actuator Control system - Forced Limited Power
There are two potentiometers located on either side of the throttle pedal which control the respective left and right bank throttle plate actuators
You need to get a hold of a scanner to be sure. Another way is to remove the intake plenums and have someone view the throttle plates to verify movement while the pedal is depressed with the key in position two. If a second observer is not available a mirror will work.
It may be something else entirely but from my own personal experience a potentiometer seems likely. I replaced the Throttle Pedal Assembly with a servicable unit. Normal function was restored, all fault codes cleared.
P2105, Throttle Actuator Control System - Forced Engine Shutdown
P2106, Throttle Actuator Control system - Forced Limited Power
There are two potentiometers located on either side of the throttle pedal which control the respective left and right bank throttle plate actuators
You need to get a hold of a scanner to be sure. Another way is to remove the intake plenums and have someone view the throttle plates to verify movement while the pedal is depressed with the key in position two. If a second observer is not available a mirror will work.
It may be something else entirely but from my own personal experience a potentiometer seems likely. I replaced the Throttle Pedal Assembly with a servicable unit. Normal function was restored, all fault codes cleared.
Last edited by drivergmx; 06-12-2016 at 12:39 AM.
#3
06-12-2016, 07:46 AM
#4
06-12-2016, 04:07 PM
Registered User
Join Date: Oct 2014
Location: Northeastern Pennsylvania, USA
Posts: 138
Rep Power: 17
yvr, Good find! I never heard about this issue with the CRM. I wonder if this component is listed as rebuild-able at MAS? If so, it could be fixed at a cost far less then that of a replacement...
#6
06-12-2016, 07:13 PM
Registered User
Join Date: Oct 2014
Location: Northeastern Pennsylvania, USA
Posts: 138
Rep Power: 17
Call My Auto Repair Solutions in Georgia and see if they can repair it for you. Quick turn around, very affordable.
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