The Innova 3120 handheld scanner has recently garnered attention, particularly among users attempting to utilize it on 94 or 95 F-body vehicles. Prompted by these user reports, we decided to conduct a hands-on review of the Innova 3120 to assess its performance, specifically focusing on its compatibility and effectiveness with these classic models. This review aims to provide a detailed, unbiased evaluation to help you make an informed decision.
The Innova 3120 arrives in practical black plastic zippered cases, separating the handheld unit and OBD2 cable from the OBD1 cable and adapters. The inclusion of batteries is a welcome addition, though the accompanying manual is notably brief, directing users to download a more comprehensive version from the innova.com website. The scanner head features a connector for cable attachment, with a dedicated single-piece OBD2 cable and a generic OBD1 cable paired with various adapters to ensure broad compatibility.
Alt: Innova 3120 OBD2 scanner kit showcasing handheld device and diagnostic cable.
Navigating the Innova 3120 is facilitated by a blue backlit LCD monochrome display, capable of showing approximately ten lines of data at once. The interface incorporates nine buttons and three LED indicators. Its size is comparable to a standard TV remote, making it reasonably compact for handheld use. However, the button interface presents some usability challenges. Navigation relies primarily on UP and DOWN buttons, which can become cumbersome when scrolling through extensive lists of options. This is particularly noticeable within the DTC display screen, which is equipped with only a single DOWN navigation button. The regular UP and DOWN buttons in this context are reassigned to scrolling through potentially lengthy DTC description text, rather than menu navigation.
For the purpose of this review, we will concentrate on the scanner’s performance with OBD1 systems, specifically the 94 and 95 LT1 F-cars. Our benchmark tools for comparison include a Tech 2 clone and the Scan9495 PC application, both recognized for their reliability and accuracy in diagnosing these vehicle systems.
Unfortunately, initial tests reveal significant issues with the Innova 3120’s performance on these targeted vehicles, despite their explicit inclusion in the scanner’s compatibility list. When connected to an LT1 PCM bench test, deliberately set to have no trouble codes, the Innova 3120 incorrectly reported a series of Diagnostic Trouble Codes (DTCs): 45, 44, 43, 42, 41, 55, 54, 53, and 52. While each code was accompanied by a corresponding description, all were demonstrably false positives. Under correct operation, the scanner should have indicated “No codes.” To further investigate, a code 22 was intentionally induced in the PCM. In response, the 3120 added DTC 34 to the list, again, an incorrect reading.
Alt: Innova 3120 OBD2 scanner LCD screen displaying device menu options in blue backlight.
Data line analysis using a sniffer confirmed that the Innova 3120 was indeed sending the correct data requests and the PCM was responding with accurate data. The problem clearly resides in the scanner’s misinterpretation of the received data. Extensive testing followed, involving attempts to retrieve correct readings by cycling through nearly every conceivable combination of vehicle year settings (93, 94, and 95) on the 3120. This process eventually identified the erroneous vehicle group being utilized by the scanner in place of the 94/95 F-car. The substituted group was identified as the 4.3L (LB4), 5.7L (L05), and 7.4L (L19) engines found in Type C, K, G, and P light/medium duty trucks (data-stream definition A219). Every piece of information from multiple forced DTCs on the test bench was found to correlate with the incorrectly displayed DTCs based on this truck definition. Notably, data bit positions aligned between the incorrect DTCs and certain truck parameters; for example, on the 94 F-car, the bit indicating “Heated Windshield Request ON/OFF” was located in the same data position as the truck’s DTC 45 set bit. Unfortunately, this cross-referencing approach offers limited utility, applicable to only about ten DTCs. This limitation stems from the intermingling of other data within the DTC data stream that doesn’t conform to the data type used for these alternative vehicles. Consequently, creating a comprehensive DTC conversion list as a workaround would not be practically feasible. Further investigation into alternative solutions is warranted. Information regarding alternative vehicle selections that yield correct readings would be highly appreciated.
It is important to note that variations in falsely reported codes beyond the initial nine observed are possible. This variability arises because the data bits in the affected location represent dynamic parameters that can change. For instance, the displayed DTCs can fluctuate based on the gearshift selector position.
Regarding DTC erasure for 94/95 F-cars, the Innova 3120 proves ineffective. Upon selecting the erase function, the scanner simply displays instructions to follow the manufacturer’s recommended procedure for code clearing, which typically involves methods external to the scanner itself (e.g., fuse removal).
While OBD1 operation on 94/95 F-cars presents significant inaccuracies, the OBD2 functionality of the Innova 3120 is anticipated to be more reliable. A subsequent evaluation focusing on its OBD2 capabilities is planned to provide a more complete assessment of this tool’s overall diagnostic utility.
In conclusion, while the Innova 3120 presents itself as a versatile diagnostic tool, our review reveals critical shortcomings in its OBD1 performance with 94-95 F-body vehicles. The scanner’s misinterpretation of data leads to consistently false DTC readings, rendering it unreliable for accurate diagnostics on these specific models. OBD2 functionality remains to be tested, but for owners of 94-95 F-cars, caution is advised regarding the Innova 3120’s OBD1 diagnostic capabilities.
