No Start Nissan

Michael Mobile Technician Clinton, Utah Posted   Latest  
Case Study
Electrical
2012 Nissan Altima S 2.5L (QR25DE) 6-spd (RS6F52A)
No Crank / No Start

I got called out to a bank repo lot. They had a Nissan Altima that was not starting. The backstory is that the bank had called a locksmith out to program a new key for the car due to it not starting with the original key. When the locksmith could not get the key to program it was taken to the local dealer. It remained at the dealer for 2 months. The dealer finally recommended a new PCM. The bank became frustrated and brought the vehicle back to the lot.

The symptom was that the dash would light up but when the start button was pushed the car would not start. The dash would only light up when the key was in the slot. None of the lock / unlock /panic features would work on either key. The battery was flat dead. After connecting a jump box I first checked to see if the keys were registered. They did not show that they were. It seemed strange that the dash would light up with incorrect keys. I then went through some factory tests within the Consult tool. The first round the result was there was a bad brake switch, the second that there may be a problem with the BCM. When watching the data, the brake switch seemed fine. The whole situation was not making sense. I told the lot supervisor that I needed to do some research and get back to them.

After some research I discovered that the brake switch was a common problem. Nearly every report on a no start said that the brake switch was the culprit. None of the reports stated that the wireless functions were inoperative. I had also watched the scan data and both elements of the brake switch were changing state. I checked on the price of the switch, reported the cost of repair and asked the lot supervisor if we could try one. He gave a thumbs up. I purchased a factory switch and installed it. No start, no change in operation.

I decided to try programming the keys again with the new brake switch installed. Success! The keys were registered quite easily. The vehicle started. The lock / unlock / panic worked with the new key but not the original. The original still needed to be in the slot to start the car. The new key worked without being in the slot.

My theory is that The original key did not operate because of the faulty brake switch. Additionally the radio function of the key had died. All the keys were erased as part of the programming process. The locksmith started the process but because the brake switch was glitchy it prevented the process from finishing. Even though there were no codes the vehicle was stuck in programming mode. Once the brake switch was replaced, the programming process which includes pressing the brake pedal was able to be completed. I have a happy customer and all is well.

+11
Joel Diagnostician
Soquel, California
Joel Default
 

did you scope the brake switch signals to find out if were glitches on siganal or voltage drop, interesting because pids for it were good to certain point as the computer was not happy with those signals

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Michael Mobile Technician
Clinton, Utah
Michael Default
 

Hard to do good work in a parking lot. There were cars stacked next to it so access was difficult. I agree it would have been a best practice to verify.

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Chris Technician
Bryans Road, Maryland
Chris Default
 

Great write up and nice fix !

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Adrean Diagnostician
Bakersfield, California
Adrean Default
 

I had one with a bad brake switch and It wouldn’t let me program the key as well .. I noticed when I looked at the rear of the car and noticed the brake lights on.. don’t recall to well but remember the push button switch wouldnt go to lock or something and during the proceudre it needed to go to lock

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