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Kristina’s 2002 Chevy Impala Passlock Fix
Kristina opened her message with a paragraph that will be familiar to anybody who has lived with this fault:
“If you are reading this testimonial, you have likely went out in the wee hours of the morning to make sure your car starts at least 10 minutes before you really have to leave for work. Or you make sure you have a passenger when you stop to refuel so you won’t have to push your vehicle away from the gas pump by yourself.“
That second sentence is the one. It is not a story about a car that will not start. It is a story about arranging your entire day around a car that might not.
It did not start on the day they bought it
They bought a 2002 Chevy Impala for their son to commute to college.
“When we went to pick the car up, it didn’t start. We spoke with the mechanic, bought the car anyway and figured at some point we would replace the ignition cylinder. Sure enough the car started to experience more than its share of ‘no start’ episodes.”
“After owning it for 7 months, we replaced the ignition cylinder. The car was perfect for several weeks, then the problem started all over again. The mechanic did a reset on the electronic system, but that did not help either.”
Perfect for several weeks. That is the pattern that costs people the most money, because it makes every repair look like it worked.
What the dealership said
At their mechanic’s suggestion they took it to the dealer for a proper diagnosis. The dealer told them to replace the ignition cylinder. They explained they already had.
“they suggested that we replace the cylinder housing ($700+) then the BCM. ‘This is really just hit or miss until we find the problem,’ they told us. Not exactly the ‘diagnosis’ we were expecting.”
We could not have put it better. Hit or miss, at seven hundred dollars a swing, on a car they had bought for a student.
“The sad part of the entire circumstance was the car was solid, ran well and actually looked fairly decent, perfect for a new driver with a short commute.”
Then they started it five more times for fun
They found the PRO Module through a GM mechanic’s forum, and Kristina did her homework before ordering:
“Prior to ordering the product, I had a very in-depth conversation with a customer service representative. He was helpful, timely in answering emails and even referred questions to his mechanic instead of shooting off an answer in the dark.“
“We installed it into the system per the instructions, held our breath, did the code relearn process and said a prayer before turning the ignition key after the last 10 minute wait. The car started immediately. Just for fun, we started 5 more times in a row. That was over a week ago and the car has been perfect ever since.”
“Thank you to the staff of Pro Module for your honesty, transparency and production of a great product. We appreciate your ingenuity in helping to fix a problem that is so prevalent with so little professional help to fix.”
Kristina B.
Why the cylinder replacement bought them weeks, not years
Passlock reads a resistance value generated in the ignition lock cylinder and compares it to a value stored in the Body Control Module. A new cylinder produces a fresh, clean value, which is why the car behaved for a while.
But the BCM is still holding an old stored value, the rest of the circuit is still twenty years old, and the comparison still has to pass every single time you turn the key. Replace the cylinder and you have reset the clock, not removed the mechanism.
That is why the dealer could only offer hit or miss. There is no faulty part to find. There is a measurement that no longer agrees with itself.
If you have a 2000 to 2005 Impala or Monte Carlo
The wiring is in the 2000 to 2005 Chevrolet Impala and Monte Carlo installation guide. The BCM is under the dash, far left, above the parking brake pedal, with three connectors.
If a shop has offered you the hit or miss approach, identify your system first and read why the cheaper workarounds do not hold. Both are free, and both are cheaper than a cylinder housing.
