P0966

P0966 is the Pressure Control Solenoid B Control Circuit High — TCM commands the driver and reads circuit voltage stuck high (open circuit, no current flowing when current was expected), which means an open in the wiring, an open solenoid winding, a pushed-back pin at the case connector, or a TCM driver that's gone open. Cheapest-first: check the case connector itself before doing anything else — pushed-back terminals from prior repairs and corroded pins from ATF migration are the #1 root cause and cost nothing to find. With the connector unplugged, ohm the PCS-B solenoid pin-pair at the case side; healthy spec is 8-30 ohms cold (3-7 ohms GM force-motor, 4-6 ohms Chrysler/Toyota PWM linear, 5-12 ohms Aisin). Infinite ohms = open winding, replace solenoid (or pack). In-spec resistance at the case = the open is upstream — back-probe the harness between TCM and case connector and ohm each leg end-to-end; anything over 5 ohms wire-resistance on a short run means a corroded splice or pin. Check ohms-to-ground on each pin too (>100k ohms expected on a floating circuit). Active current at full command should be 0.5-1.5 A — read zero current with the driver commanded on and the open is confirmed. Expensive-misdiagnosis caveat: on Chrysler 545RFE/68RFE the integrated solenoid pack frequently sets P0966 when a single internal solder joint inside the pack opens up from thermal cycling — externally everything looks fine, the pigtail ohms correct on cold cars, but at operating temp the joint opens and the code sets. This is not field-repairable; full solenoid-pack replacement is the only fix, and technicians who chase external wiring on this trans frequently come-back the customer 200 miles later when the same code returns hot.

Vehicle-specific patterns: 1996-2007 GM 4L60E/4L65E throws P0966 from the case-connector pin-fit losing tension after repeated unplugging during routine service — GM bulletin guidance is to replace the case-connector body, not just the wires, $40-80 part. 2003-2010 Dodge Ram 1500/2500 with the 545RFE and 2007-up 68RFE shows P0966 routinely in the 70,000-150,000 mile band — the solenoid pack is replaced as a unit per Chrysler service procedure, $500-900 parts plus labor at independents per AAMCO data, $1,000-1,400 at dealers. 2007-2013 Ram HD with the Aisin AS69RC throws P0966 from a known internal pigtail solder-joint break inside the valve-body solenoid carrier, valve-body R&R required, $800-1,400. 2001-2010 GM HD with the Allison 1000 (LCT1000) sets the equivalent from a broken wire at the PCS-2 or PCS-3 internal harness flange-chafe location — repair the harness before the solenoid. Estimated repair: $300 to $1,500.