P2737: CVT binary-pump control fails its two-mode pressure comparison

P2737 describes CVT binary-pump pressure-control performance in the reviewed GM source. The controller compares average primary- and secondary-pulley pressures between half-capacity and full-capacity pump modes. This is a system-response test, not simply an electrical circuit-range check despite the generic title.

Both pump modes must be observed

The sequence first allows half mode to stabilize for more than one second, then full mode for more than two seconds. Only after both stages are complete does it compare the mode-dependent average pressures with calibrated thresholds. More than three failed counts establishes the listed result.

A single pressure reading without pump-mode context cannot reproduce that comparison. A change in pressure between modes must also be evaluated against the correct selected-range thresholds, rather than a single invented universal limit.

Stability is deliberately controlled

Initial eligibility includes vehicle speed below 2 mph, accelerator position below 0.5%, engine speed between 600 and 1,200 rpm, and a primed pump. Engine-speed stability and multiple pressure-control fault exclusions also matter. The supporting table makes stabilization time temperature-dependent: two seconds at 50°C and 1.5 seconds at 60°C.

The main table has unclear temperature-maintenance wording, and some later pressure-comparison limits are not clearly specified. Exact reproducing limits therefore need the applicable service procedure; this article does not fill those gaps by assumption.

Verification should confirm completion of both commanded modes and acceptable pressure response in the correct CVT calibration. The source lists Type B, two-trip behavior without isolating a replacement component.

Source and applicability

Keep the stated transmission function and source calibration separate from other applications. GM diagnostic table, PDF page 1186. GM diagnostic table, PDF page 1187. GM diagnostic table, PDF page 1188. GM diagnostic table, PDF page 1189. GM diagnostic table, PDF page 1190. GM diagnostic table, PDF page 1191. GM diagnostic table, PDF page 1292.