CAN resistor adapter

Jaltest OBD4 — CAN Resistor Adapter

The OBD4 is the CAN Resistor Adapter for the Jaltest diagnostic system, listed at $85.00 MSRP in the official 2025 Cojali USA pricelist. This adapter is a diagnostic tool accessory that addresses one of the more frustrating failure modes in CAN bus diagnostics: the inability to communicate with a vehicle's network because the bus termination is incomplete.

CAN (Controller Area Network) bus systems require termination resistors at each end of the network — typically 120 ohms — to function correctly. When a vehicle's CAN bus is missing a terminator, has a faulty one, or when a technician is working with a CAN network segment that isn't properly terminated in the test configuration, the diagnostic interface can't establish communication. The OBD4 CAN Resistor Adapter allows the Jaltest system to work with these configurations by providing the correct termination, enabling communication where it would otherwise fail.

What This Adapter Solves

CAN bus termination issues show up in real shop work in specific situations:

• Bench testing and ECU-out diagnostics: When an ECU or module is removed from the vehicle and bench-tested, the CAN bus it's normally connected to doesn't exist. Without proper termination, the module may not communicate. The OBD4 provides that termination so bench diagnostics can proceed.
• Partial teardown diagnostics: If part of the vehicle's CAN network is disconnected during a repair, the remaining segment may lack proper termination. Adding the OBD4 restores the terminated state of the active portion of the network.
• Troubleshooting CAN bus faults: The OBD4 can be used as a test tool to isolate whether a communication failure is caused by missing termination versus an actual network fault.
• Network integrity testing: Technicians can use the adapter to verify CAN bus resistance (should read ~60 ohms across CANH/CANL with both end terminators in place) when checking for wiring faults.

Product Specifications

• Part Number: OBD4
• Description: CAN Resistor Adapter
• MSRP (2025 Cojali USA Pricelist): $85.00
• Function: Provides CAN bus termination to enable communication on unterminated or partially terminated networks
• Compatible with: Jaltest diagnostic system (CV, OHW, AGV, MHE, Marine platforms)

Why CAN Termination Matters for Diagnostics

Modern commercial vehicles, agricultural equipment, and off-highway machinery use CAN bus extensively. A Class 8 truck may have multiple CAN networks connecting the engine ECU, transmission controller, ABS module, aftertreatment system, body computer, and instrument cluster. Each network requires proper termination to maintain signal integrity at the diagnostic speeds Jaltest uses to communicate.

When termination is missing or faulty, symptoms include:

• Diagnostic software unable to detect the vehicle or specific modules
• Communication timeout errors even though the vehicle runs and operates normally
• Intermittent module connectivity during a diagnostic session
• Inability to perform active tests that require sustained two-way communication

The OBD4 addresses the termination side of this problem, eliminating it as a variable so you can focus on the actual diagnostic work.

Where It Fits in Jaltest's Tool Ecosystem

The OBD4 is listed in the Jaltest cable and adapter section of the official Cojali USA 2025 Pricelist alongside other diagnostic cables and adapters. It's not a cable that connects to a specific vehicle brand — it's a utility adapter used with the Jaltest interface when specific CAN bus termination conditions require it.

For shops that do bench ECU work, handle electrical/network troubleshooting on heavy equipment, or regularly encounter CAN communication failures as part of their diagnostic workflow, the OBD4 is a practical tool to have available alongside the main Jaltest cable set.

Why Buy From OEM Diagnostic Tools?

We've been supplying Jaltest tools and accessories to shops, fleets, and independent technicians since 2016. The OBD4 is the kind of adapter that seems minor until you need it — and when you need it, you need it immediately. We stock it, it ships free, and our tech line at 866-217-0063 is available if you want to talk through whether this adapter fits your specific situation before you order. Full warranty, real people, straight answers.

Call 866-217-0063 for quick answers and help!