SureTrack Real Fix: Self-inflicted Drain

Real Fixes from Mitchell 1’s SureTrack® expert information resource are documented issues from actual shop repair orders and community discussions. Read on to see how SureTrack can help you correct issues that are not easily diagnosed using OEM information alone. SureTrack is available at no additional cost in our ProDemand product.

With the amount of electronic gadgets available for cars today it can be hard to track down something that is causing an issue. SureTrack community member ProAutoValdosta had a Honda CR-V in their shop that would not start after sitting for a few days. They could see a draw on the system but could not find the cause at first. They posed the question to the community, and with the help of fellow community member Sleazen and others, they were able to resolve the issue quickly.

The following Community Fix summarizes the interaction between members of the community that led to the solution.

2009 Honda CR-V EX 2.4L

Battery drain, removed module.

Customer states that car will not start after sitting 2 or 3 days.

Diagnostic Steps Performed/Parts Replaced
The owner states that if the vehicle is not started every two to three days, the battery will discharge and the vehicle has to be jumped. We tested the battery, it tested good, but the owner replaced it anyway. We tested the charging system, and it tested fine. We performed an amp draw test and the draw hovers around 50 mA…not out of spec, but close. We checked several common known issues such as the A/C compressor clutch relay and the Bluetooth module. Apparently discharged batteries are a common issue with these due to undersized batteries? What is a normal amp draw for a 2009 CR-V? My general rule of thumb is “no more than 50 mA”. Several times we intentionally “woke up” the system and then let it go back to sleep and every time the draw stays around 50 mA. Pulling fuse #23 in the underhood panel drops the drain to 0 mA. It controls the audio unit, navigation (which this car does not have), the immobilizer, and the MICU (which controls the lighting/delay/locks).

Best Answer from Community Member Sleazen
Generally, on a car with a small battery, you don’t want any more than 30ma. If you can find the source of the draw you’re seeing, you may solve the problem.

It turns out that the owner had an aftermarket Bluetooth OBD2 scanner module hooked up under the dash, probably for an app on their phone. This module was causing the drain.

Unhooking the Bluetooth module dropped the drain down to less than 10 mA when it’s “asleep”! Charged the battery and returned vehicle to customer.

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About the Author

Nick Taylor

Nick Taylor is the SureTrack Community Administrator and a Senior Applications Specialist at Mitchell 1 with over 25 years of experience with electronic repair data systems. Nick previously worked in the automotive dismantling and engine rebuilding industries.