busta

Here are my symptoms, I can crank (turn the engine over) the motor by supplying battery voltage directly to the solenoid and the engine starts up. When I turn the key to start I get 12v at the yellow crank wire of the ignition sw. At the Theft Deterrent Relay I measure 12v at the red supply wire, when I turn the ign. to start I get 12v at the yellow PNP transmission wire and at the yellow/black - bcm wire, nothing at the purple wire.

I tried a new TDR same results. I double checked all the grounds and they're in good shape, battery is fully charged and load tested.

Also when I turn the key to start I hear the under hood ign.relay#43 energize, and dash relay #37 energize? But never the TDR.

No burnt fuses, I have pulled and reseated all of them and swapped Relays around with matching ones. Vats has been deleted from PCM.

I've searched through most of the no start threads with no luck.

Any ideas?

Y2Kvert4me

The yellow/black wire to the TDR relay is switched ground from the BCM.

When not starting, there should be no continuity to ground on that yellow/black wire.
When attempting to crank, the BCM should connect that wire to ground, allowing the relay to energize.

At no time should the yellow/black wire be showing +12v. The solid yellow wire, yes...but the relay won't energize even with 12v if the other side of the coil has no ground.

It sure sounds like the BCM is inhibiting the start. Just as a means for troubleshooting, you could jumper the yellow/black wire at the TDR to a good ground inside the car. This will effectively bypass the BCM. If my suspicion is correct, the car should then crank.

I don't know if it will run or drive doing this, but it would tell you for sure what's going on. Why the BCM is inhibiting start could be due to a bad or dirty resistor pellet in the key...or the ign switch that reads it, or worst case, a junk BCM.

busta

I tried bypassing the yellow/blk wire with a ground directly to that terminal on the TDR still no crank? Supposedly Vats has been disabled from the PCM. It's a brand new PCM that was flashed by a member on the forum.

BlackZ06

Did you go through the "Vehicle Theft Deterrent Password Learn" procedure ???

The BCM and PCM agree on a new "password" every time you start the engine. If the PCM is replaced the two computers no longer have an agreed upon password, they are out of synch. Check and see if you have a P1631 set .... the BCM is inhibiting engine start.

Check for other codes .... but note that VATS is controlled by the BCM .... I'm unsure what you mean that VATS has been programmed out of the PCM.

Bill Curlee

Your getting some really good info here!!!

Who did it and how was VATS programmed out of your BCM?

If you have some one sit in the drivers seat and make all the conditions necessary to normally start the car Clutch pressed, key on, (A4, park,) etc and you GROUND the "YELLOW / BLACK" wire, the car should start.

The reason your NOT seeing 12 VDC on the PURPLE wire is the TDR is not energizing. Once the relay energizes, it will connect the red wire to the purple wire through the internal contact inside the relay.

BC

busta

I tried the relearn procedure still no crank. I tried adding a ground directly to the TDR yellow/black wire also no crank.

'waitforme' did the PCM programming I thought he said some security features could programmed out, I could be wrong.

I only have a diablo scanner but I'm able to read vin and DTC codes. The list of codes thrown was probably due to me starting it from going directly to the starter.

The only code that seemed related was this:
P0562 - System Voltage Low? Any other suggestions?

BlackZ06

You went through the 30 minute "password relearn" procedure ??????

You don't need a scanner to read codes from a C5 Corvette, and in fact the following procedure will display codes that most scanners can't display ......

https://www.corvetteforum.com/techti...D=26&TopicID=1

Post ALL the codes displayed .... that will tell you why/if the BCM is preventing engine start. Not telling us what codes are posted is like going to the doctor and saying "guess what's wrong with me?" .... we can't help you if you won't give us information.

System Low Voltage .... ya think your battery might be a little weak ???

busta

P0101 - Mass Air Flow (MAF) Sensor Performance
P0102 - Mass Air Flow (MAF) Sensor Circuit Low Frequency
P0103 - Mass Air Flow (MAF) Sensor Circuit High Frequency
P0106 - Manifold Absolute Pressure (MAP) System Performance
P0108 - Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage
P0125 - Engine Coolant Temperature (ECT) Insufficient for Closed Loop Fuel Control
P0128 - Coolant Thermostat Below Thermostat Regulating Temperature
P0131 - Heated Oxygen Sensor (HO2S) Circuit Low Voltage Bank 1 Sensor 1
P0132 - Heated Oxygen Sensor (HO2S) Circuit High Voltage Bank 1 Sensor 1
P0133 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 1
P0134 - Heated Oxygen Sensor (HO2S) Circuit Insufficient Activity Bank 1 Sensor 1
P0135 - Heated Oxygen Sensor (HO2S) Heater Performance Bank 1 Sensor 1
P0152 - Heated Oxygen Sensor (HO2S) Circuit High Voltage Bank 2 Sensor 1
P0153 - Heated Oxygen Sensor (HO2S) Slow Response Bank 2 Sensor 1
P0154 - Heated Oxygen Sensor (HO2S) Circuit Insufficient Activity Bank 2 Sensor 1
P0155 - Heated Oxygen Sensor (HO2S) Heater Performance Bank 2 Sensor 1
P0171 - Fuel Trim System Lean Bank 1
P0172 - Fuel Trim System Rich Bank 1
P0174 - Fuel Trim System Lean Bank 2
P0175 - Fuel Trim System Rich Bank 2
P0200 - Injector Control Circuit
P0230 - Fuel Pump Relay Control Circuit
P0300 - Engine Misfire Detected
P0325 - PCM Knock Sensor Circuit
P0327 - Knock Sensor Circuit Low Voltage
P0332 - Knock Sensor 2 Circuit Low Input (Bank 2)
P0335 - CKP Sensor A Circuit Performance
P0336 - Crankshaft Position (CKP) Sensor A Performance
P0341 - Camshaft Position (CMP) Sensor Performance
P0342 - Camshaft Position Sensor Circuit Low Input
P0343 - Camshaft Position Sensor Circuit High Input
P0562 - System Voltage Low
P0608 - Control Module VSS Output "A" Malfunction
P0654 - Engine RPM Output Circuit Malfunction
P0706 - Trans Range Switch Performance
P0711 - TFT Sensor Circuit Range/Performance
P0713 - Transmission Fluid Temperature (TFT) Sensor Circuit High Input
P0719 - Brake Switch Circuit Low Input
P0724 - Brake Switch Circuit High Input
P0740 - TCC Enable Solenoid Circuit Electrical
P0742 - TCC System Stuck On
P0751 - 1-2 Shift Solenoid Valve Performance - No First or Fourth Gear
P0752 - 1-2 Shift Solenoid Valve Performance - No Second or Third Gear
P0753 - 1-2 Shift Solenoid Circuit Electrical
P0756 - 2-3 Shift Solenoid Valve Performance - No First or Second Gear
P0757 - 2-3 Shift Solenoid Valve Performance - No Third or Fourth Gear
P0758 - 2-3 Shift Solenoid Circuit Electrical
P0785 - 3-2 Shift Solenoid Circuit Electrical
P1111 - Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage

BlackZ06

Looks to me like you used a scanner, there are no codes above Pxxxx listed .... USE THE DIC and procedure I posted above .... none of these codes should cause a "no crank" (though I'm still checking that) ....

busta

I currently don't have a cluster I'm waiting for one to come in though hopefully this week. I only have a MIL mocked up from the pcm.

BlackZ06

How did you do the 30 minute re-learn procedure ??? Normally you watch the security warning light to determine when the BCM timer has ended for each 10 minute period ..... if this procedure isn't done properly (and I'm guessing it wasn't) the BCM will not energize the TDR.

Once you have a cluster, I'd recommend re-trying the 30 minute password relearn process (If you don't have the procedure PM me and I will send it to you). Also check the BCM and the other computers for DTC posted, I'm betting the BCM is what is preventing your engine from cranking.

busta

I received a cluster today and plugged it in. I performed the 3 -10 minutes cycles for the bcm relearn according to the posts regarding this procedure.

When I turn the key to on the DIC displays Pull Key wait 10 Seconds, I did that then Service Steering Column Lock, Reduced Engine power, and Service Engine Soon, I also have check gauges light on? Still doesn't start

I tried to pull codes from the dic but I was unable to. I followed the procedure from the sticky post? The column and cluster is from an earlier model not sure if that makes a difference? The column is only hooked up electrically. Any Ideas?

BlackZ06

Wow ... where to start ..... so to speak ....

First thought is "do you have a Service Manual" ????

That would help you immensely as the Service Manual contains both wiring diagrams and explanations of how things work.

The starting sequence for the vehicle is complex, as it involves multiple "checks" before the vehicle can start.

When you first insert the key, several things happen. When you try and turn the key, the physical cuts in the key have to match the lock itself, or the key won't turn. Once the key is "matched" to the lock it moves to the ACC and then RUN, then START positions.

In no certain order, certain things have to occur ....

The BCM commands and monitors the column lock. It commands the column to unlock and verifies that it did so. If the column unlock fails, the BCM posts the "SERVICE COLUMN LOCK" message, and tells the PCM to inhibit fuel if the engine is already started. If the engine is started alraeady, and you try to drive the vehicle, when it reaches 1.5 MPH the PCM will shut off the fuel supply.

The BCM reads the resistance of the VATS pellet installed in your key. If the resistance is incorrect, or cannot be read, the BCM will not enable the VTD relay, which means you get a "no crank" condition.

There are other "safeguards" built into the system. The BCM and PCM have to exchange a password that changes every time the engine starts. That's why you have to do the "password relearn" when you change either computer. If the two computers don't agree on the password, the engine will crank, but the PCM will not deliver fuel.

Bottom line, it is difficult to "hack" together the engine start. You need to ensure that the Class2 serial data link is working (so all the computers can exchange the data needed for an engine start), you need to ensure the column lock system is working correctly, and you need to ensure that the BCM is reading the VATS data correctly.

The C5 Corvette start is intentionally complex, so a thief can't do something "simple" like just installing a new ignition lock or a new BCM. A thief would have to install multiple components, and spend the time (like the 30 minute password re-learn) to defeat the system, and that even assumes they understand it .....

I would seriously recommend you get a copy of the Service Manual (actually 3 books) to help you in diagnosing this. You are fighting with a system that wants everything to be "perfect" before the engine can start. You need a key with the right VATS resistance, and you need the ability to read the DTC data, that will help immensely in figuring out the problem.

Best of luck, keep posting as you work through this .....

Bill Curlee

BLACKZO6 is 100% correct!!

BC

busta

This is for something I'm building I do have the service manual and schematics.

Some of the parts that I'm using are not original to the car. The engine, engine wiring and dash wiring harness' are matched for the 2002 automatic car. The bcm, pcm, and both fuse boxes are from an 02.

The PCM is new and was programmed by 'wait4me'. The ignition s/w is not a match to the bcm. Both of the keys measure 7.5KOhms. The cluster and steering column I have are from an earlier C5. Maybe these aren't interchangeable I was told they were? Should I also be looking to try 14 more keys too thanks

BlackZ06

If you have access to a Tech2, and you can power the BCM, you can see which key code the BCM is looking for ... in the BCM it is called "Passkey Register Signal" .... and lists the resistance the BCM is looking for. Otherwise, there is a post here somewhere on how to try different resistors which you can buy at Radio Shack cheap, to see what the BCM resistance is expecting. I'll see if I can find the thread and post a link in another response.

The steering column shouldn't be an issue, and earlier clusters did not have the pinouts for the HUD, but I'll assume you don't care about that. I tried looking to see in the parts list if the HUD are different by year, but the GM parts list only says the IPC are sold from AC Delco Service Centers (so they can set the correct odometer before shipping) and doesn't list a part number. However, several people have installed the "newer" IPC in earlier C5 to get the HUD function, and I've not heard of any problems there.

When you insert the key, does the Security light come on or blink ??? If so, then it is almost definately the pellet.

busta

Unfortunately I don't have a Tech 2
When I plug the key in I get the "remove key for 10 seconds" msg, which leads me to believe that it is checking for the correct key.

If I remove it and put it back in the Security light does not come on or flash. If I turn the key to the on position it does come on but does not flash. So the relearn steps only sync up the BCM with PCM? Also does the wrong key prevent the DIC from displaying the fault codes?

BlackZ06

OK, I tried and can't find the post I was looking for ... so ... In your Service Manual turn to the section called Theft Deterrent and go to the electric schematics. There should be a schematic called "Theft Deterrent System Schematics (Ignition key signals and Trunk Release switch).

Note in the upper right corner it shows the ignition lock and a key. On my year the two wires feeding Key resistor sensor terminals are PURPLE/WHITE (Circuit 1074) and WHITE/BLACK (Circuit 1073)

What you want to do is ...

A) unplug those wires from the ignition lock.
B) Connect a resistor between the two wires ..... I'll come back to that in a sec
C) Turn key in ignition and see if the TDR energizes.
D) If it does not .... Turn key OFF and wait AT LEAST 3 minutes
E) try next resistance level

You will have to do this up to a possible 15 times, trying each resistance until you find the one the BCM is programed for.

The 15 levels are:

VATS #, Resistance in ohms

1 392
2 523
3 681
4 887
5 1.13k
6 1.47k
7 1.87k
8 2.37k
9 3.01k
10 3.74k
11 4.75k
12 6.04k
13 7.50k
14 9.53k
15 11.80k

You need resistors that will get you within plus or minus 10 percent of these values. You could theoretically buy 15 differerent resistors, but the easiest way is to "daisy chain" several together to get the right resistance .... so if you want 7.5k ohms, wire a 5.0k ohm and a 2.5k ohm together serially (one after the other) to get the wanted resistance. By the way, you can probably skip the 7.5k ohm test ... seems that one doesn't work ....

When you find the correct resistance, you need to order blanks of that number (if 6.04k works, you order a #12 key blank) and then get a locksmith to cut the blank to match the notches in your current key. Use a decent locksmith, I wouldn't trust someone like a discount hardware place to do it, for example.

Does this make sense ????

BlackZ06

Ah hah .... try this link ... it will help ...

http://www.corvetteactioncenter.com/...ad.php?t=88349

Better with pictures (tho it looks like he has a C4, but the concept is the same) .....

maestro300

A friend of mine had this same problem on his Camaro SS. I just in-line attached the resistor and fixed the issue... however this disables the security rather than just getting a new key.