P0976

P0976 is the Shift Solenoid B Control Circuit Low — the TCM commands SS-B and reads circuit voltage stuck low (short to ground in the wire, shorted winding, or a TCM driver that's latched on). Cheapest-first: unplug the case connector, clear the code, and key-cycle the TCM. If the circuit-low fault clears with SS-B unplugged, the short is between the TCM and the case connector (harness chafe), and the solenoid is innocent — chase the wire. If the fault persists with the connector unplugged, the TCM driver is failed; rare but it happens. With the connector plugged back in, ohm SS-B pin-to-pin: 8-30 ohms cold is the typical spec band (19-31 ohms GM 4L60E, 9-16 ohms Ford 4R75W, 11-15 ohms Chrysler 545RFE pack, 10-15 ohms Toyota A340/A750). Anything under 3 ohms pin-to-pin = shorted winding, solenoid (or pack) replacement. In-spec ohms pin-to-pin with the code still setting = ohm pin-to-ground on each leg looking for <100k ohms — that's the classic ATF-migration short, where overheated fluid creeps up the wire insulation and shorts the conductor to the case. Active current at full command should be 0.5-1.5 A; pegged-current readings (2-3 A or driver-trip into protection) confirm the short. Expensive-misdiagnosis caveat: on Chrysler 545RFE/68RFE a P0976 short-to-ground often originates inside the solenoid-pack body where the winding insulation has cooked from years of high-temp ATF — the pack is sealed and not field-serviceable, full pack replacement is the only repair, and any tech who tries to splice or repin will be back in 1,000 miles with the same code. RAM 545RFE/68RFE solenoid-pack replacement runs $500-900 parts plus labor at independents per AAMCO/RepairPal cost data.

Vehicle-specific patterns: 1996-2007 GM 4L60E/4L65E sets P0976 from internal-harness chafe at the case-rib pass-through where the harness rides on a sharp aluminum edge under load — repair with internal harness kit, $80-150 plus pan-drop labor. 2003-2010 Dodge Ram 1500/2500 with the 545RFE and 2007-up 68RFE shows P0976 frequently in the 70k-150k mile band as pack windings break down — pack replacement $500-900 parts plus labor at independents. 2007-2013 Ram HD with Aisin AS69RC throws P0976 from SS-B winding insulation breakdown after a hot-fluid event, valve-body R&R, $800-1,400. 2001-2010 GM HD with the Allison 1000 sets the LCT1000 equivalent from PCS-2/PCS-3 wire chafe at the case-flange ridge — Allison Transmission service guidance directs technicians to repair the chafe before condemning the solenoid. Estimated repair: $300 to $1,500.