As a Volvo 940 owner, you might be wondering about modern diagnostic capabilities for your trusty vehicle. The On-Board Diagnostics II (OBD2) system became a standard feature in cars sold in the USA from 1996 onwards. But what about European models like the Volvo 940, particularly those from the mid-to-late 90s? One Volvo enthusiast shared their hands-on experience trying to connect an OBD2 scanner to their 1997 Volvo 940 LPT, sold in Sweden, to understand the diagnostic landscape for these classic cars.
Decoding OBD2 and Volvo 940 Models
The introduction of OBD2 was a significant step forward in automotive diagnostics, offering a standardized way to access vehicle data for emissions and engine performance. While the 1996 mandate in the US pushed manufacturers to adopt OBD2, the situation could be different for cars in other markets. Our Volvo 940 owner suspected their Swedish market car might not fully comply with OBD2 standards, prompting them to investigate further when faced with an engine issue. Experiencing intermittent engine stalls, they sought a modern diagnostic approach to pinpoint the problem, moving beyond older Volvo diagnostic methods.
The OBD2 Scanner Experiment and Unexpected Results
Initially informed about Volvo’s older LED readout diagnostic tools, which were reportedly not available on their 940 model, the owner turned to the internet and discovered the world of OBD2 scanners. Inspired by resources like Alex C. Peper’s website (www.obd-2.com), they acquired an OBD2 scan tool and located the OBD2 connector in their Volvo 940’s armrest. However, upon plugging in the scanner, they encountered a setback – no connection could be established with the car’s Engine Control Unit (ECU). This led to initial concerns about the functionality of the new scan tool itself.
To verify the scanner, a clever test was conducted using a friend’s 1999 Volvo V70, a model explicitly labeled as OBD2 compliant. Connecting the same scan tool to the V70 yielded immediate success, with data flowing smoothly to a laptop and diagnostic software working perfectly. This successful test on the Volvo V70 highlighted a crucial difference and reinforced the question about OBD2 compatibility in the older Volvo 940.
Domestic vs. Export Models and ECU Considerations
The contrasting results between the Volvo 940 and V70 led to an important conclusion: potential variations exist between domestic and export market cars, possibly in areas like the ECU’s EPROM or coding. Despite the OBD2 connector physically being present in the 1997 Volvo 940, it might not be fully wired or programmed for complete OBD2 communication in the same way as later, OBD2-standard models. The owner noted that the OBD2 connector in their Volvo 940 LPT model 1997 appeared to be connected to the Bosch 0280000984 HL 2.4 ECU, referencing specific pins (pin 7 ISO-9141-2 K line and pin 15 ISO-9141-2 L line), suggesting a partial or different implementation of diagnostic protocols.
This raises questions for other Volvo 940 owners, particularly those with models from 1995-1998, especially in markets outside the USA. Experiences with OBD2 scanners on these specific Volvo 940 models would be valuable in understanding the extent of OBD2 compatibility across the range. Interestingly, the root cause of the initial engine stalling issue was eventually traced back to a simple problem: a bad solder joint in the fuel pump relay – a reminder that sometimes, even without advanced diagnostics, traditional troubleshooting can be effective. The Volvo 940 owner’s journey highlights the nuances of OBD2 implementation in older vehicles and encourages further exploration within the Volvo 940 community.
