What Does P0947 Mean?
DTC P0947 indicates the hydraulic pump relay circuit is detected as low, meaning the TCM sees an abnormally low voltage on the relay control or power circuit. This typically suggests the relay coil circuit or pump power feed has a short to ground or excessive current draw that is pulling the voltage below the acceptable threshold. The pump may not operate correctly or at all under this condition.
Safety Warning
A low relay circuit can prevent the hydraulic pump from operating or cause it to run erratically. This may result in inadequate pressure for shifting and clutch engagement. In severe cases, the vehicle may not be drivable. A short to ground also presents a risk of wiring damage or blown fuses.
Common Causes
30%
Relay control wire shorted to ground in the wiring harness
25%
Relay coil internally shorted causing excessive current draw
20%
Pump motor winding short causing excessive current through the relay
15%
Water or contamination in relay socket causing partial short
10%
TCM relay driver circuit shorted internally
Diagnostic Steps
1
Step 1: Remove the relay and check if the code condition clears (relay coil removed from circuit). If the circuit reads normal with the relay removed, the relay itself is likely shorted.
2
Step 2: Test the relay coil resistance with a multimeter. A reading significantly below the specification (or near 0 ohms) indicates a shorted coil. Replace the relay.
3
Step 3: With the relay removed, check the relay control wire for a short to ground between the relay socket and the TCM using a multimeter on the ohms setting.
4
Step 4: Inspect the relay socket and surrounding wiring for moisture, contamination, or physical damage that could cause a short circuit.
5
Step 5: Install a new relay and monitor the circuit voltage during operation. If the low-circuit condition persists, measure the pump motor current draw to rule out a shorted motor winding.
Estimated Repair Cost
$80 - $500
Parts + labor, varies by vehicle and location
DTC P0947 indicates the hydraulic pump relay circuit is detected as low, meaning the TCM sees an abnormally low voltage on the relay control or power circuit. This typically suggests the relay coil circuit or pump power feed has a short to ground or excessive current draw that is pulling the voltage...
The most common cause of P0947 (Hydraulic Pump Relay Circuit Low) is: Relay control wire shorted to ground in the wiring harness
Typical repair costs for P0947 range from $80 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A low relay circuit can prevent the hydraulic pump from operating or cause it to run erratically. This may result in inadequate pressure for shifting and clutch engagement. In severe cases, the vehicle may not be drivable. A short to ground also presents a risk of wiring damage or blown fuses.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0947 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission / Clutch Hydraulic System
Difficulty
Type
Generic (SAE)
Recommended Tools
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