P0946 Fault Code

Hydraulic Pump Relay Circuit Range/Performance

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0946 fault code indicates an issue with the hydraulic pump relay circuit's range or performance in a vehicle's transmission system. This code can affect the operation of the hydraulic pump, which is crucial for maintaining proper pressure within the transmission.

• This fault code is primarily associated with automatic transmissions, where the hydraulic system plays a key role in gear shifting and overall performance.
• When the hydraulic pump relay circuit fails, it can lead to inadequate fluid pressure for transmission operation, potentially causing erratic shifting or complete transmission failure.

What are the symptoms of the P0946 code?

Drivers experiencing the P0946 fault code may notice a variety of symptoms including:

• Unusual or harsh shifting patterns in the transmission.
• Warning lights on the dashboard, particularly the check engine light.
• Slipping gears or difficulty in engaging certain gears.
• Overheating of the transmission fluid due to insufficient pressure.
• A complete loss of transmission function in severe cases.

What causes the P0946 code?

Several factors can lead to the P0946 fault code, including:

• A malfunctioning hydraulic pump relay that fails to provide adequate power or signals to the hydraulic pump.
• Short circuits or open circuits within the hydraulic pump relay circuit, disrupting the flow of electricity.
• Wiring issues, such as damaged connectors or insulation breakdown, can interfere with the relay's operation.
• A faulty hydraulic pump that may not be providing the expected pressure output even if the relay is working properly.
• Problems with the vehicle's engine control module (ECM) that may misinterpret inputs from the hydraulic pump relay.

How to fix P0946?

To resolve the P0946 fault code, the following steps are commonly recommended:

• Start with a thorough inspection of the hydraulic pump relay and its circuit for any signs of damage.
• Test and replace the hydraulic pump relay if it is determined to be faulty.
• Check all associated wiring and connectors for continuity and signs of wear or damage, repairing or replacing as necessary.
• If the hydraulic pump itself is found to be malfunctioning, consider replacing it to restore functionality.
• Clear the fault code after repairs and test drive the vehicle to confirm that the issue has been resolved.