Matthew’s 2001 Silverado: Why Half a Bypass Doesn’t Hold

Matthew Manrique’s story, sent to us in August 2016, spans eight years with a 2001 Silverado. It is the clearest account in our archive of the difference between bypassing part of the security system and removing it, because he lived through both.

2008: ten minutes that almost cost him

“Occasionally, the truck would just refuse to start… After 10 minutes of jiggling wires, swapping relays, and scratching my head, the truck would start–leaving me to scratch my head some more. By the third or fourth time it happened, I realized that it simply would not start until those ten minutes had passed.”

“I was in the military at the time, and being late was a big deal. There were a couple times that the ten minute wait almost got me in some real trouble.”

A scan turned up a code reading roughly “invalid passcode”. The dealer knew the fault instantly and quoted about $600 for a new ignition lock cylinder.

The $150 half-fix

“I took the truck to my mechanic, who is a long time friend that I trust. He told me that he had seen this problem before, and that he could bypass the ignition switch for about $150… My ‘security’ light stayed on constantly though. It seemed like a small price to pay.”

“The fix worked for a year or two. The funny thing was that every six months or so, the truck would still refuse to start for ten minutes. I brushed it off as a fluke the first few times, and then it became more frequent again.”

This is the crucial passage. His mechanic is competent and honest, and his bypass genuinely worked, at the ignition end. But Passlock has two ends, and the Body Control Module was still in the circuit, still comparing, still empowered to cut the fuel. A bypass that leaves the judging module in charge has not removed the problem, it has muffled it. When it came back, the mechanic called it correctly: the BCM, and only the dealer could help, at roughly $800.

The search term that ended it

“Frustrated at the thought of paying so much money to have a system ‘repaired’ (and knowing that it still would not work because of the initial bypass of the ignition lock cylinder), I turned to google. That is when my fortunes finally turned. A quick internet search of ‘BCM bypass’ turned up the solution… $300 to permanently bypass the system seemed much better than $800 to put a band-aid on it.”

“I spent about 1 hour installing the system, and another half hour on the re-learn procedure… I cranked the engine, and it came to life. As a bonus, the ‘security’ light is off for the first time in years.”

His advice, better than ours

“If you are mechanically inclined in any way, and if you are confident enough in your wiring abilities that you are even considering doing this bypass yourself, then you will probably have no problem doing the job. If you have no idea what you are doing, then pay a professional to install the PRO Module for you. It is a huge relief to have the GM anti-theft nightmare behind me. I love my truck again.”

If you have one of these trucks

The NEWROCKIES PRO Module is a full bypass: the sensor, the wiring and the BCM’s veto all leave the starting decision together, which is why there is nothing left to come back every six months. For the 1999 to 2002 new-style Silverado and its Suburban, Tahoe, Yukon and Sierra siblings, the wiring is here: 1999-2002 installation guide.

Related stories on the blog. Same wiring: Jerrald’s 2002 Avalanche and Dale’s 1999 Suburban.

Read more customer stories →