Hydraulic Pump Relay Circuit High
The ECU detected abnormally high voltage in the hydraulic pump relay circuit, like a short circuit pushing too much electrical power through. This prevents the hydraulic pump from operating correctly, affecting systems that depend on it.
The ECM monitors the voltage signal from the hydraulic pump relay circuit during operation. It expects a normal operating range with proper voltage drop across the relay when activated. When voltage exceeds the threshold, the ECM registers a high circuit fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Relay Circuit Voltage | 0.5-4.8V when active | >5.2V or short to battery |
| Relay Coil Resistance | 70-100 ohms | <50 ohms or >150 ohms |
Code P0948 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0948 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.