Code 9092 \ Battery Faulty or not installed + Visit Workshop Batt
Thread Starter
Junior Member
Joined: Aug 2020
Posts: 54
Likes: 5
2006 E350
EDIT - Solved! Code 9092 \ Battery Faulty or not installed + Visit Workshop Batt
So here's my issue....2006 W211 E350
Visit Workshop \ Batt is showing on the display.
Code 9092 \ Aux Battery Faulty or not installed
STATUS:
Main Battery has 14.0V running
Aux Battery has 12.8V running or off - (This is a new battery)
Polyswitch fuse has continuity
Voltage readings on firewall relay terminals read 14.1v and 12.8v running
When I cycle the aux relay sw, I get 14.1 at both terminals (and the battery.)
The original aux battery completely died, wouldn't charge at all.
Live data shows .3V for the Aux Battery, and I assume this is what's triggering the code.
Any ideas on the cause? Does anyone know where the AUX voltage reading comes from?
Thanks in advance.
Visit Workshop \ Batt is showing on the display.
Code 9092 \ Aux Battery Faulty or not installed
STATUS:
Main Battery has 14.0V running
Aux Battery has 12.8V running or off - (This is a new battery)
Polyswitch fuse has continuity
Voltage readings on firewall relay terminals read 14.1v and 12.8v running
When I cycle the aux relay sw, I get 14.1 at both terminals (and the battery.)
The original aux battery completely died, wouldn't charge at all.
Live data shows .3V for the Aux Battery, and I assume this is what's triggering the code.
Any ideas on the cause? Does anyone know where the AUX voltage reading comes from?
Thanks in advance.
Last edited by Brianstrange; Oct 14, 2020 at 03:05 PM.
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Joined: Feb 2014
Posts: 6,190
Likes: 1,550
From: MA
2008 E350 4Matic, 2011 E350 4matic
Have the aux battery load tested. Any auto parts store should be able to do this for free. It's possible to read full voltage but fail a load test. Usually a bad cell. Happens even with new batteries. Or you aux battery isn't charged, what's the voltage when the car is off? If it's not charged, put it on a charger.
Thread Starter
Junior Member
Joined: Aug 2020
Posts: 54
Likes: 5
2006 E350
Have the aux battery load tested. Any auto parts store should be able to do this for free. It's possible to read full voltage but fail a load test. Usually a bad cell. Happens even with new batteries. Or you aux battery isn't charged, what's the voltage when the car is off? If it's not charged, put it on a charger.
Thread Starter
Junior Member
Joined: Aug 2020
Posts: 54
Likes: 5
2006 E350
Thank you. I'm thinking the issue is either the wire that senses the power for the Aux Battery, or the Battery Control Module. I should have mentioned that I discovered corrosion on the BCM pins, some pins disintegrated all together. I have since replaced it (with a used "Tested" unit) and cleaned the harness terminals. Is there a pinout of the circuit for the BCM wires? I'd love to be able to run pin to pin continuity tests.
Last edited by Brianstrange; Oct 12, 2020 at 10:53 AM.
Thread Starter
Junior Member
Joined: Aug 2020
Posts: 54
Likes: 5
2006 E350
No visible damage to wires in either spot. Can you tell me if the wire with the polyfuse is the actual wire that brings voltage to the Battery control module? I'm thinking that if it is, I should read voltage at the BCM connector, and if it's the same as the battery terminals, my problem can be ruled as a ground issue, poor connect to, or a bad BCM, correct?
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Thread Starter
Junior Member
Joined: Aug 2020
Posts: 54
Likes: 5
2006 E350
UPDATED! Problem Found!!!!
Alright, so I had the Visit Workshop Battery Message on the dash. When I first tried to address this, I replaced the aux battery which was dead. This did not remove the error. A few weeks ago, research had me check the connector to the Battery Control Module, and there was heavy green corrosion that actually disintegrated some pins. I installed a new BCM, and cleaned the connector pins. The Workshop message stayed on. Later, I got a Foxwell 530, and cleared all codes, the voltage reading thru the scan tool was .3V, The Aux battery had 12.7. I sprayed electrical cleaner on the BCM connector and plugged it back in....the light went out! Not long after, the light came back on, but last night I confirmed that I had 12.7 volts at the wire the BCM measures voltage (Scan tool still reading .3V) My issue were the terminal pins (which I originally cleaned well, but not well enough) on the BCM Harness.
Suggestion! - If you have a funky Visit Workshop Battery error, and your Alternator, Main Battery and Aux Battery have good voltage, a simple voltage test to the Red\Purple wire (while unplugged from the BCM) can confirm a few things.
1) It should read the same voltage as the AUX Battery, this is good. Clean all of the terminals well on both the BCM and the BCM Connector.
2) If it reads 0 volts, you could have a faulty Polyswitch fuse (self resetting breaker) at the Aux battery, or a short to ground in the Red\Purple voltage wire between the Polyswitch and the BCM.
I hope my story helps you.
Suggestion! - If you have a funky Visit Workshop Battery error, and your Alternator, Main Battery and Aux Battery have good voltage, a simple voltage test to the Red\Purple wire (while unplugged from the BCM) can confirm a few things.
1) It should read the same voltage as the AUX Battery, this is good. Clean all of the terminals well on both the BCM and the BCM Connector.
2) If it reads 0 volts, you could have a faulty Polyswitch fuse (self resetting breaker) at the Aux battery, or a short to ground in the Red\Purple voltage wire between the Polyswitch and the BCM.
I hope my story helps you.
Last edited by Brianstrange; Oct 14, 2020 at 03:03 PM.
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