P0965

P0965 is the Pressure Control Solenoid B Control Circuit Low — the TCM commands the PCS-B driver and reads circuit voltage below the threshold (typically under 0.5 V with the solenoid commanded off, or near-zero current when current was expected), which means a short to ground in the wiring, a shorted solenoid winding, or a stuck-on TCM driver. Cheapest-first: unplug the case connector and clear the code; if the fault clears with the solenoid unplugged but the TCM still reads circuit-low, the short is between TCM and case connector (harness or chafe point) and the solenoid is innocent. If the code stays with the connector unplugged, the TCM driver itself is shorted — rare but real. With the connector plugged back in, ohm the PCS-B pin pair: healthy spec is 8-30 ohms cold (3-7 ohms GM force-motor; 4-6 ohms Toyota/Chrysler PWM linear; 5-12 ohms Aisin). Less than 3 ohms pin-to-pin = shorted solenoid winding, replace. In-spec resistance with the code still setting = ohm pin-to-ground on each leg and look for under 100k ohms — that's ATF migration up the harness shorting the wire to case (extremely common on high-mileage units that have seen overheated fluid). Active current at full command should be 0.5-1.5 A; if you read 2-3 A or the TCM trips into protection, that's the short. Expensive-misdiagnosis caveat: on Chrysler 545RFE/68RFE the solenoid-pack pigtail and the pack itself are sealed together as one assembly — a P0965 short-to-ground inside the pack body cannot be repaired wire-by-wire, you replace the whole pack ($500-900 parts plus labor per AAMCO survey data on the platform), and chasing a single circuit on this trans is a known time-sink that costs customers more than the right repair.

Vehicle-specific patterns: 1996-2007 GM 4L60E in the Silverado/Tahoe/Trailblazer line throws P0965 from internal harness chafe at the case-rib pass-through (the harness ribs ride on a sharp aluminum edge under load and wear through after 100k+), repaired with internal harness kit $80-150 plus pan-drop labor. 2003-2010 Dodge Ram 1500/2500 with the 545RFE and 2007-up 68RFE see P0965 frequently in the 70,000-150,000 mile window — the solenoid-pack TCM-side connector is a documented failure point and the pack is replaced as an assembly ($500-900 parts plus labor per RepairPal/AAMCO data). 2007-2013 Ram HD with the Aisin AS69RC throws P0965 from PCS-B winding insulation breakdown after a hot-fluid event, valve-body R&R required. 2001-2010 GM HD with the Allison 1000 sets the LCT1000 equivalent from PCS-2 or PCS-3 wire chafing at the case-flange ridge — Allison TSB-style guidance from Allison Transmission directs technicians to repair the chafe before condemning the solenoid. Estimated repair: $300 to $1,500.