Does the obd2 port require a terminating resistor? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kipps · 10-15-2019, 11:56 PM

I'm finding very little info on this. I've got a gen iv 5.3 with an E38 ecm.

I'm planning to use a manual transmission, so there will be no transmission control module. Thus, the only two devices on the data bus are the ecm and the obd2 port. The ecm supposedly has a terminating resistor internal to itself. Am I supposed to add a resistor to the obd2 port? If so, how and what size?

prodjay10 · 10-16-2019, 01:38 AM

I’m not sure if this will answer your question but when I started the engine before installing it I didn’t connect the transmission and wired up the obd2 to pull codes. It worked for me. I didn’t need a resistor.

**clay68c10** · 10-16-2019, 06:51 AM

You shouldn't have to add one. The OBD plug isn't a CAN node or a module, just an access point for reading data.

10-15-2019, 11:56 PM	#1
kipps Registered User Join Date: Jul 2014 Location: North-central Virginia Posts: 1,104	Does the obd2 port require a terminating resistor? I'm finding very little info on this. I've got a gen iv 5.3 with an E38 ecm. I'm planning to use a manual transmission, so there will be no transmission control module. Thus, the only two devices on the data bus are the ecm and the obd2 port. The ecm supposedly has a terminating resistor internal to itself. Am I supposed to add a resistor to the obd2 port? If so, how and what size? __________________ 1987 C6P V20 truck, 2010 LMG 5.3, AFM delete, 2010 Camaro exhaust manifolds, 1997 nv4500, 1991 np241c, hydroboost, 2005 14bff axle & driveshaft, drop-n-lock gooseneck, 4.10 gears, stock suspension, rims, and tires. Still a work in progress. Any questions or suggestions are welcome!

10-16-2019, 01:38 AM	#2
prodjay10 Registered User Join Date: Jun 2016 Location: Phoenix AZ Posts: 429	Re: Does the obd2 port require a terminating resistor? I’m not sure if this will answer your question but when I started the engine before installing it I didn’t connect the transmission and wired up the obd2 to pull codes. It worked for me. I didn’t need a resistor.

10-16-2019, 06:51 AM	#3
clay68c10 Senior Member Join Date: Aug 2004 Location: Centennial, CO Posts: 2,996	Re: Does the obd2 port require a terminating resistor? You shouldn't have to add one. The OBD plug isn't a CAN node or a module, just an access point for reading data. __________________ ClusterTruck: 68 C10 Bought in 89, wrecked in 03. Slow low $ rebuild started '17. 6.0 & TKO http://67-72chevytrucks.com/vboard/s...d.php?t=788602 93 K1500 Short Step, 350, NV4500, EBL flash ECU. Vortec heads & roller cam someday... 05 Jeep Wrangler Unlimited. 3” lift & 6-speed 02 E320 the insurance total “free car” 13 Tahoe LTZ



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