Going on a bug hunt

Certainly, the most notable adventures we’ve braved in the past several years happened when I agreed to take on a 2001 VW Beetle with a start-and-die problem. Nobody else had worked on the car; she had simply gone out one morning to start the bug and it simply started and died repeatedly.

These bugs are as cute as a pan full of kittens – I cut my teeth on the old VW beetle but all it shares with this one is the basic outside shape.

For New Beetle buggers, that’s points to an immobilizer (passive anti-theft) problem, but all we had to work with on that platform was an OBDII scan tool. Up to that point, I had never purchased the European software for any of my tools, because we see maybe one European car a year and too many Asian and domestic models to count. Besides that, the guy I assigned to this job was a second semester student who was fairly sharp, but had no idea what the bug-shaped flashing light on the cluster meant. Since he didn’t mention anything about it and I didn’t look at the dash indicators myself, we wound up going after the crank sensor code we pulled from the Nemisys. There were no immobilizer codes that came out of that DTC retrieval, but then, you won’t get those from the OBDII generic interface on this car anyway. 

Today’s vehicles have a lot of peculiar warning lights, some that flash and some that simply illuminate – this isn’t an ISO symbol (although it looks like one). It’s bug-shaped with a key in the wheel well and it flashes when it thinks somebody is stealing the car with a bogus key.

Checking the spark, we found that it would start popping and then go away while the engine still was spinning.  Identifix® posts spoke at great length of checking the AC voltage generated by the Crank Sensor, which was just less than the minimum of 800 mv. We replaced the sensor and got that voltage up to 1,500 mv. That probably fixed the stored crank sensor code, but it didn’t fix the car. So we called the hotline and spoke to the European car expert. My discussion with him about the code and the spark issue led the engineer to send me after the PCM, because, in his words, “they like to burn up.”  He said if the PCM was destroyed, you could see it by removing the PCM and opening it to eyeball the circuit board. 

The PCM on this car is located under the top dash panel right behind the cluster. Well, we did that, and it was fine as far as we could see (but I wondered if maybe it could fail in some less evident fashion). Further testing at the PCM connectors proved that the crank sensor signal was making it all the way to the PCM the whole time. We sewed up that part of our investigation really fast and moved on. Everybody reading these words knows how catastrophic it can be to replace an engine controller on a hope and a prayer.

With the Ross-Tech® software, and Joey’s cable you have to know which measuring blocks to select, but once you learn that, extracting codes from the various modules is simple – these were the first codes we got from the cluster.

I mentioned to the hotline guy my concern that the problem might be immobilizer related, and he said the immobilizer typically doesn’t shut off the spark; it simply kills the fuel injectors. I found out that was hooey. This one did indeed kill the spark and the injectors on this particular Beetle. Since we now (too late) recognized the flashing bug/key light for what it was, I called Mike, a very sharp guy from a shop across town, and he brought his Snap-On box that had all the bells and whistles. While he did get immobilizer-related codes from the PCM, he couldn’t talk to the instrument cluster. Not at all. Since this was a quid-pro-quo deal, I thanked him, promised him a favor in return, and he headed back to his shop. In the Snap-On tester’s defense, I later discovered that unless you have a battery charger connected to this car so as to have really strong supply voltage, the PCM will communicate, but the cluster won’t talk to a scanner. In cases like this, I like to use the Midtronics ripple-free charger that I bought for flashing engine controllers. Because the battery was weak, I kept it connected for most of this job.

This was the initial message we got from the PCM after we finished with the rabbit trail of chasing the generic OBD2 crank sensor code Nemisys gave us.  Note that this code actually pointed to the cluster as a possible problem.

Then I called the big gunner who sold me that charger – Joey Hendrich of AEtools.us. If he doesn’t have the answer, he’ll find it for you. (Incidentally, his tech support is free if you buy tools from him and I do). Hendrich and I met in Massachusetts at Craig VanBatenburg’s hybrid training. We were on the same four-man team in that class, and I found out just what a dynamo he is at solving really tough problems. During one of the 12-hour shop sessions, I even saw him enter the “back door” of a failed Hybrid Battery ECU with his laptop, determine the protocol it was supposed to be using and then he wake that controller up to bring it back to life. We all were stunned by that accomplishment.m

He told me three very important pieces of information about the Beetle. 

After attempting to start the car, we got these two codes, leading me astray – I kept assuming the key was a problem and initially had them fetch me a new key from the dealer.

The best tool to talk to a VW the right way is the VAG-COM from Ross-Tech®, which he just so happened to have. I bought one.

Even after yanking the codes, if the problem turned out to be an immobilizer problem, I’d be out of business if I couldn’t extract the four-digit pin from the cluster (needed for programming a new key or cluster if one was needed). He had a tool for that, too. 

The cluster frequently is the problem on these platforms, and a replacement cluster would be the wisest first choice. 

I should have listened to Hendrich’s third piece of advice. As it was, I was boneheaded enough to get sidetracked by DTCs that told me the key signal was weak and/or the lock cylinder pickup coil was bad.

We had an immobilizer problem of some kind to be sure, because the cluster was complaining that it couldn’t see the key. The pickup coil seemed like a logical possibility — after all, it receives and transmits the code. Further, as we used the VAG-COM we discovered that while this 2001 Beetle had a serial number beyond the 430,000 VIN threshold that separates Immobilizer 2 from Immobilizer 3 platforms, it was outfitted with Immobilizer 2, which made no sense at all, until later.

Little did I know at this point that the cluster’s funky little brain had lost its ability to see the key, even with a good key and a good pickup coil.

At the same time, we got these codes from the Engine Controller, which muddied our thinking even further – sorting this stuff out can be a pain on an unfamiliar platform.

I had the customer get me another key just for grins, which they obtained from the Pensacola, Fla., VW dealer for $60. Having made the discovery during my wait for the key that it was an Immo 2 system in spite of the serial number, I called the Pensacola VW parts department, and the associate I spoke with assured me that the same key would work with either Immo 2 or Immo 3, because both part numbers were now the same. But while one of Hendrich’s sources refuted that, he told me the dealer probably was right. They must have had old data, because the VW dealer turned out to be right in the end, but my doubts drove me to snag a used 2001 Beetle steering column (complete with a chipped switchblade key) just for grins. I was trying to cover all my bases in my own misguided, silly way. And now I would need the second, more expensive cable-and-dongle package to retrieve the PIN. I gave Hendrich my credit card number and he zipped it out to me overnight via FedEx.

With the VAGtacho software and cable, we hacked into the cluster, chose the appropriate cluster from a long list (process of elimination), and read the pin code, but this cluster still couldn’t read the key even after I retrieved the pin and entered it into the Ross-Tech software during the key programming process.  You won’t get anywhere without the PIN, and the VAGtacho is the best way I’ve found to get it.  The very next week, I fixed a Diesel Jetta with it – sometimes VWs just forget their key and have to have programming done to fix it.

Using the second cable Hendrich sent, I plugged in the dongle, loaded the software with some remote help from Hendrich’s guy at AEtools and proceeded to retrieve the cluster’s pin number, which turned out to be 2886. I then used the Ross-Tech software (which is tricky to use, but there are videos on Ross-Tech’s website) to attempt to erase all preexisting keys and program the new one. Big problem — it wouldn’t work, so I caved in and ordered a cluster from the local salvage yard for $125, smacking myself for not listening to Hendrich in the first place.

With the cluster on its way, I first installed the used ignition lock cylinder from the salvage yard column thinking the antenna on the original lock cylinder might be an issue. An attempt to program the used key and cylinder to the original cluster was a dismal failure, and now neither of the other keys would fit. I was hung using the one that came with the used lock cylinder.

This is the disassembled salvage yard key (I had to buy the whole steering column to get it and a lock cylinder).  The chip was damaged in this key for some unexplained reason even though there was no external damage to the housing.

The salvage yard asked when I was ordering the cluster if it was manual or automatic transmission. It had a PRNDL stick in the floor, so I told them automatic. While that was true, it turned out to be a bad question where the cluster for this particular car was concerned. The cluster they sent immediately threw a bunch of DTCs about a missing transmission controller and whatnot. The replacement cluster’s part number ended in 901 and the original cluster’s part number ended in 906, a fact that I noticed even before I installed it. 

When I called the salvage yard and gave them that part number information, they informed me that this car had been outfitted with cluster for a manual transmission Beetle (PRNDL stick notwithstanding), and I ascertained that the automatic transmission on this one must be fully hydraulic. The bug guys had stuffed the Immo 2 cluster on it because it had no transmission electronics. Then there was that 430000 VIN threshold that turned out to be wrong. This was a circumstantial land mine of the first magnitude, and now the customer had a car rented because the job was taking so long. I seemed to be stuck on stupid or something, but I gritted my teeth determined not to give up, because that’s what real mechanics do, isn’t it? After all, I had students watching this whole exercise with intense interest, and if my own professionalism wasn’t enough to motivate me, the desire to set an example should be. And it was. I tightened my gloves and stayed in the fight.

This is her original key and chip; we removed this chip (very carefully – it’s glued in there).

I got the right cluster, but still couldn’t get it to take the key, even though measuring blocks 21, 22 and 23 in the cluster indicated the key was OK – I hadn’t received those results before.  Another call to Hendrich sealed the deal. He said to disassemble the key I was using and use just the blade of that key with the head of the new key held near to it. As it was, I found that the stupid chip in the used salvage yard key was cracked (how it got that way is kind of amazing since it’s so protectively mounted), and I felt sort of silly for obtaining it to begin with. I taped the good chip from the customer’s original key to the blade of the key that fit the replacement cylinder and the programming went like a song. Had I ordered a replacement cluster to begin with, my journey (and the fight) would have been over quickly, but now I know things I would never have learned otherwise.

Then I went the extra mile by reassembling her original key with the good chip, swapped out the girl’s lock cylinder so her original key and the new one they bought would fit, and programmed them both. Now she had two good keys, no flashing bug light and a car that would start and run. In the end, I was a heck of a lot smarter about how to handle old VW Immobilizer systems. What I learned from this exercise was something I already knew, and it was quite simple. Pay attention when somebody with more experience is talking. You’d think I would have learned that after nearly 40 years in this business, but we all take wrong turns from time to time.

And we taped it to the salvage yard key – it programmed perfectly with the PIN and the Ross-Tech® software.

I got a visit from the Beetle owner two days later. She said her car was running and starting fine, but that within seven miles, the speedometer needle was wagging wildly all over the dial. I put in a call to the salvage yard and told them to get me another cluster, and that one worked fine. With my freshly earned experience, I was able to whiz through marrying the new cluster with the keys in record time (for me).

Sometimes salvage yard parts save our bacon – sometimes they make it so we can’t afford to even buy bacon. In this case, it seems that both were true. One way or another it feels good to win in the end. And God bless an extremely patient customer. She trusted me during phases of this operation when I didn’t even trust myself.

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