Circuit/System Testing

WARNING: This page is about a different car, the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, 2018 Chevrolet Suburban 3500 HD, and 2018 Chevrolet Suburban. However, it is still accessible from the selected car via links, so may be relevant.

Verify the transmission line pressures are within the specified ranges. Refer to Line Pressure Check .
- If pressures are not within range
  Refer to Fluid Pressure High or Low .
- Go to next step: If pressures are within range
Ignition OFF. Remove the Q8 Control Solenoid Valve Assembly.
Verify a pressure change occurs for each solenoid when performing the solenoid test. Refer to Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test .
- If a pressure change does not occur
  Replace the Q8 Control Solenoid Valve Assembly.
- Go to next step: If a pressure does occur
Verify the conditions listed below do not exist. Carefully inspect each component for that condition. Repair or replace as necessary.

P2723 or P2724 - Control Valve Upper Body Assembly (304)

1-2-3-4 Clutch Regulator Valve (337) stuck/sticking - debris, binding, damaged valve, or scored bore.

P2723 - Q8 Control Solenoid Valve Assembly (314)

Refer to document PIP 4304A. DTC P2723 may be set with DTC P0878.

P2723 or P2724 - Q8 Control Solenoid Valve Assembly (314)

O-ring seal leaking.
Valve body filter plate assembly cracked, blocked, or damaged gasket seal.

P2723 - Control Valve Upper Lower Assembly (351)

Clutch Select Valve 3 (352) stuck/sticking - debris, binding, damaged valve, or scored bore.

P2723 - A/Trans Fluid Pump Cover Assembly (219)

Pump Tower Seals (230) damaged/leaking.

P2723 - 1-2-3-4 and 3-5-R Clutch Housing Assembly (51)

1-2-3-4 Clutch Piston (414) cracked/damaged/leaking.
Housing/hub weld cracked/leaking.
1-2-3-4 Clutch Backing Plate Retaining Ring (429) not seated/oriented, causing clutch pack/piston over travel.

P2723 - Control (with body and valve) Valve Assembly (21)

Valve Body to Pump Transfer Seal Assembly (19) damaged/leaking.

P2723 - Torque Converter (w/Fluid Pump) Housing Assembly (2)

Fluid pump housing vanes/rotor/slide damaged/scored.
Fluid pump or torque converter overstressed due to high temperatures.

P2723 - Automatic Transmission Fluid Filter Assembly (26)

Oil filter (26) or filter seal (25) loose or damaged.