For automotive enthusiasts and DIY mechanics, a reliable car scanner is an indispensable tool. The Innova 3120 handheld scanner is often touted as a versatile option, compatible with a wide range of vehicles, including older OBD1 systems. However, recent user reports and our in-depth testing have revealed significant issues when using the Innova 3120 on specific OBD1 vehicles, particularly 94 and 95 F-body cars (like Chevrolet Camaro and Pontiac Firebird) equipped with the LT1 engine. This review delves into our findings, highlighting the scanner’s shortcomings in this specific application and providing crucial information for potential buyers considering the Innova 3120 for older vehicles.
First Impressions and Initial Setup
Upon receiving the Innova 3120, the packaging is practical and well-organized. It comes in two zippered black plastic cases, separating the handheld unit and OBD2 cable from the OBD1 cable and adapter set. Batteries are included, which is a welcome addition, and a quick start guide is provided. However, the included manual is indeed brief, as noted in user feedback, and directs users to the innova.com website for the complete manual. The scanner itself features a connector at the top for cable attachment. The OBD2 cable is a single, unified piece, while the OBD1 cable is a generic type intended for use with various adapters depending on the vehicle. The display is a blue backlit monochrome LCD, capable of showing approximately ten lines of data at once. Navigation is controlled through nine buttons and three LED indicators. The physical size is comparable to a large television remote, making it reasonably easy to handle.
Usability and Design Considerations
While the Innova 3120 appears functional at first glance, the button layout and navigation prove to be less intuitive than desired. The reliance on only UP and DOWN buttons for menu navigation becomes cumbersome, especially when scrolling through lengthy lists of options. Selecting an item in the middle of a list requires numerous button presses, slowing down the diagnostic process. This design choice is further exacerbated on the DTC (Diagnostic Trouble Code) display screen, which limits navigation to a single DOWN button. The regular UP and DOWN buttons are repurposed to scroll through the potentially lengthy descriptions of the DTCs, adding another layer of complexity to what should be a straightforward task.
OBD1 Testing on 94-95 F-Cars: The Problem
Our primary focus was to evaluate the Innova 3120’s performance on OBD1 systems, specifically 94 and 95 LT1 F-cars. For comparison and validation, we utilized professional-grade diagnostic tools, including a Tech 2 clone and the Scan9495 PC application, which are known to function correctly with these vehicles.
Unfortunately, despite the Innova 3120 being listed as compatible with these vehicles, our testing revealed significant inaccuracies. When connected to a 94 LT1 PCM test bench with no actual trouble codes present, the scanner incorrectly reported a plethora of DTCs: 45, 44, 43, 42, 41, 55, 54, 53, and 52. Each of these false codes was accompanied by a description appropriate to the number, but they were entirely erroneous. The scanner should have indicated “No codes” in this scenario. To further investigate, we introduced a genuine trouble code (DTC 22) to the PCM. In response, the Innova 3120 displayed an added DTC 34, which was also incorrect.
Technical Explanation of the Issue
To understand the root cause of these inaccuracies, we employed a data sniffer to monitor the data communication line between the scanner and the PCM. This analysis confirmed that the Innova 3120 was indeed sending the correct data requests, and the PCM was responding with the correct data. The issue lies in the scanner’s misinterpretation of the data received from the 94/95 F-car PCM.
Extensive testing, involving cycling through almost every combination of vehicle year settings (93, 94, and 95) available on the Innova 3120, eventually led to the identification of the incorrect vehicle group being used by the scanner for 94/95 F-cars. Instead of the correct F-car protocol, the Innova 3120 appears to be utilizing the data-stream definition A219, which corresponds to 4.3L (LB4), 5.7L (L05), and 7.4L (L19) engines in Type C, K, G, and P light/medium-duty trucks.
This explains the consistent display of specific incorrect DTCs. For instance, data bits intended for other parameters in the 94 F-car’s data stream are being misinterpreted as DTCs from the truck protocol. An example is the “Heated Windshield Request ON/OFF” bit in the 94 F-car data, which is located in the same position as the DTC 45 set bit in the truck protocol. While some DTC cross-referencing is possible due to this data position overlap, it is limited to approximately 10 DTCs. The presence of other non-DTC information mixed within the data stream, which differs between vehicle types, prevents a comprehensive workaround through a simple DTC conversion list. Furthermore, the displayed DTCs can vary based on factors like the gearshift selector position, as these dynamic parameters can influence the data bits being misinterpreted.
OBD1 Code Erasing Limitation
Another significant limitation encountered with the Innova 3120 on 94/95 F-cars is its inability to erase trouble codes. When attempting to erase codes, the scanner simply displays instructions to follow the manufacturer’s procedure, which typically involves disconnecting the battery or pulling a specific fuse – actions that should ideally be automated by a modern scan tool. This lack of functionality further diminishes the scanner’s usefulness for these OBD1 vehicles.
OBD2 Functionality (To Be Evaluated)
While our testing has revealed critical flaws in the Innova 3120’s OBD1 performance on 94/95 F-cars, the scanner’s OBD2 capabilities remain to be thoroughly evaluated. It is plausible that the OBD2 functionality is more accurate and reliable, as OBD2 protocols are generally more standardized. However, this requires separate testing and will be addressed in future evaluations.
Conclusion: Not Recommended for 94-95 OBD1 F-Cars
Based on our rigorous testing, the Innova 3120 car scanner, despite its advertised compatibility, is not recommended for use with 94 and 95 OBD1 F-body cars, particularly those equipped with the LT1 engine. The scanner’s inability to accurately read and interpret DTCs, coupled with its failure to erase codes on these vehicles, renders it unreliable and potentially misleading for diagnosing issues. While the initial packaging and basic features are adequate, the core functionality for this specific application is severely lacking. Owners of 94-95 F-cars seeking a diagnostic scanner should consider alternative tools known to be compatible with these specific OBD1 systems, and exercise caution when relying on the Innova 3120 for these vehicles. Further investigation into the OBD2 functionality is needed to provide a complete assessment of the Innova 3120’s overall capabilities.
