The C4 Corvette CCM/BCM firmware has not been updated or improved upon since its final release in the 1996 model year. ZR1ECM.com along with PRO CAR Electronics has updated and upgraded this firmware to significantly improve the driving experience of your 1990 thru 1996 Corvette. It's called the 20:20 Update and although it's not in public release yet, it is in the Final Beta-Testing phase. Email us for more information.

Vehicle Anti-Theft System (VATS): If you've ever false-tripped your VATS while trying to start your Corvette, you have probably been forced to patiently wait 4 minutes before trying again. If you guessed wrong and turned the ignition key too soon, you were forced to wait another 4 minutes.

The 20:20 Update provides a 10 second VATS lockout for the first two consecutive false-trips. Simply remove the ignition key and wipe its resistive pellet to ensure a correct reading. Within a few short seconds you can try again. After two consecutive failures the VATS lockout resorts to a full four minute lockout.

The 20:20 Update now uses the "SECURITY" bulb to let you know exactly when the VATS lockout time has completed. No more guessing. When the "SECURITY" bulb turns off, proceed to start.

Digital Gauge Readouts: Owners of 1990 and 1991 Corvettes do not enjoy the benefit of Digital Gauge Readouts in their Cluster LCDs. This 1992 thru 1996 Driver Information Center feature provides Engine Oil Temperature, Coolant Temperature, Battery Voltage and Automatic Transmission Oil Temperature.

The 20:20 Update gives the 1990 and 1991 Corvettes the Digital Gauge Readout feature. Simply press the RANGE button on the Driver Information Center and the LCD will provide vital powertrain information exactly as it does in the 1992 thru 1996 models.

Diagnostics On-The-Fly: The 1990 thru 1996 Central Control Module provides a built-in Diagnostics Scanner. Unfortunately, the original factory design is cumbersome to use, especially while driving. Normally, before starting the engine, a jumper needs to be inserted into the ALDL or DLC connector at the base of the steering column, near the driver's knee. While stationary or test driving, the CCM provides a one-time slow readout of Current and Historic trouble codes then switches to manual mode which requires ongoing intervention from the driver to operate. In the event the jumper is removed, the Diagnostics Scanner becomes completely disabled and you're forced to turn off the engine to try again.

The 20:20 Update gives the driver, Auto-Scan On-The-Fly. Simply start the engine and stay parked or drive away. To activate the built-in scanner press the RANGE or GAUGES button on the Driver Information Center. Click through each digital gauge reading until the Diagnostics Auto-Scan activates. Unlike the slow factory version, the 20:20 Update provides trouble codes that update with a user-friendly cadence and start again when completed. If you're troubleshooting, let Auto-Scan run continuously or if you prefer, deactivate the scanner by pressing the RANGE or GAUGES button. You can start the Auto-Scan again on-the-fly whenever you choose.

With Diagnostics On-The-Fly there's no need to use a jumper wire in the ALDL or DLC port or to connect a scan tool unless you're doing in-depth vehicle analysis and/or fault diagnosis. Regardless, with the 20:20 Update there is no longer a need to turn off the engine to start a diagnostic scan process. This limitation has been removed.

Note: 1996 On-Board Diagnostic II (OBD II or OBD-2) Corvettes require a Scan Tool to read Powertrain Trouble Codes since limited codespace exists in the CCM and this has forced the exclusion of this feature. All other modules remain readable using the CCM's built-in diagnostic capabilities.

Unlimited EEPROM Writability: Back in the 1990s when a GM dealer sold a new or refurbished Central Control Module, it was imperative that it be configured after installation to that one particular Corvette, otherwise the GM TECH 1 TOOLS became locked out. This means that to this day, used CCMs are not readily transferable from one Corvette to another. A used CCM contains data in its EEPROM that essentially commits it for life, to the one Corvette it was originally installed in. Arguably, this made sense when the vehicles were new and under warranty, but decades later, this inability to reconfigure a CCM creates an unnecessary burden for any person attempting to repair or restore a 1990 thru 1996 Corvette. That is, until now.

The 20:20 Update has removed the 100 mile configuration limit. With this firmware update, any "TECH 1", "TECH 1 SERIES A" or "TECH 1A" GM Service Tool can change the EEPROM Configuration to accommodate a transfer of the CCM from one 1990 thru 1996 Corvette to another of the same model year. This means the Season Odometer, Vehicle Options, and VIN data can be readily programmed or reprogrammed to match the vehicle the CCM is moved to and the VATS/Pass-Key data can be cleared and automatically updated upon inserting the proper ignition keys.

Vanity Bootup Text: If requested with your 20:20 Update, we can customize up to 7 alpha-numeric digits on the odometer line, so when you start your Corvette, it greets you with a custom message. For example: "95VEttE", "95 VEt", "90 Zr1", "dr VEt", "40thAnn", "2 FASt", "VIN 007" etc. [Note: Since the LCD is designed for numbers, some letters are not possible.]

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