VW Polo Power Steering Fault
Three weeks off the road. A new pump already fitted. And still, the same red steering warning light glowing on the dashboard.
“It’s still showing the fault. The steering’s just as heavy.”
That’s what Mr H told the team at Cole & Miller Automotives when he called about his Volkswagen Polo. Although the pump/motor unit had already been replaced at another garage, the dashboard warning hadn’t cleared, and the power steering still wasn’t working.
Understandably, he was starting to doubt whether the issue could be fixed at all.
We booked the car into our Arlesey workshop for a full technical evaluation. That gave our team the opportunity to carry out a clean, structured diagnostic process from the beginning, using the right tools, information and test procedures to guide every step. It’s exactly how we approach complex faults, especially when a previous repair hasn’t resolved the issue.
The next step was to take a closer look at the fault and begin working through the system one stage at a time.
First Signs of a VW Polo Power Steering Fault
When Mr H’s VW Polo arrived at Cole & Miller Automotives in Arlesey, we already had a clear report of the symptoms: no power steering and a warning light on the dashboard. We then confirmed the same symptoms ourselves. The steering assistance was completely absent when manoeuvring the car, and the warning light was illuminated.
A replacement steering pump/motor unit had already been fitted. However, the warning light remained, and the steering felt just as heavy. With that background in mind, we moved on to the next stage of our assessment.
We began by reviewing previous work and performing a visual check of the steering system. With no obvious signs of fluid loss or damage to the newly installed part, we moved on to electronic testing.
We carried out a full system scan using our Volkswagen dealer-level diagnostic equipment. The scan revealed a single stored fault in the steering control module:
00816 – Power Steering Sensor (G250)
Fault code 00816 relates to a sensor signal issue within the steering system, but the presence of the code alone was not enough to confirm the underlying cause. Further investigation would be needed to determine whether the sensor itself was at fault, the pump was incorrectly matched to the vehicle, a configuration issue remained after installation or something else.
With the fault code confirmed and the symptoms consistent, we moved on to the next step in our structured diagnostic process to identify what the system was missing and why the power steering had shut down.
What Was Really Behind Fault Code 00816 Power Steering Sensor (G250)?
With the VW Polo’s symptoms confirmed and fault code 00816 logged in the system, we moved into our structured diagnostic process. Here’s how we worked through each stage of the investigation:
Step 1: Checking the Electrical Supply to the Pump Unit
Our first step was to confirm whether the pump/motor unit was receiving the electrical supply it needed to operate.
- We referred to the official Volkswagen wiring diagram to locate the main power and ground terminals at the pump connector.
- Using a multimeter and switching the ignition on, we tested both the power feed and the earth connection.
What we found:
Battery voltage was present, and the ground path was secure. The readings showed no power loss, poor continuity or wiring faults. The pump/motor unit was receiving an electrical supply, so this wasn’t the source of the problem.
Step 2: Analysing Serial Data and Module Communication
With supply confirmed, we moved on to communication checks.
- We connected our ODIS diagnostic tool, the same system used by Volkswagen main dealers, to access serial data from the steering module.
- We reviewed the module’s fault memory, scanned for additional errors, and checked the incoming data values being received by the control unit.
What we found:
The control module was live and responding. It was successfully communicating with the wider vehicle network. However, the expected signal from the power steering sensor (G250) was either missing or unreadable. The system had disabled steering assistance in response. This suggested there may be an issue with the transferring of data, but not a complete module failure.
Step 3: Verifying Part Compatibility
Since the pump/motor unit had already been replaced by another garage, it was vital to confirm that the part was compatible with this particular Polo model.
- We cross-referenced the part number on the installed unit against the vehicle’s original build information and checked it against the Volkswagen parts database.
- We also considered that VW Polo models of this generation were built with more than one steering system, and some variants require specific software or hardware formats to function correctly.
- A unit with the wrong internal configuration, even if it fits physically, can transmit data in a format the vehicle’s control module doesn’t recognise. That signal mismatch alone is enough to trigger fault code 00816.
What we found:
The fitted part didn’t match the vehicle’s original specification. Although physically similar, its configuration didn’t align with the system’s expectations. This mismatch triggered fault code 00816 and disabled the power steering.
Step 4: Reviewing the Programming and Coding Status
Even a compatible part won’t function unless it’s correctly programmed to the vehicle.
- We used ODIS to review the coding and adaptation data inside the control module and checked whether the replacement unit had been paired to the vehicle after installation.
What we found:
The module had not been coded. Without this, the steering system couldn’t recognise the sensor signal or interpret the input correctly. As a safety measure, the system disabled steering assistance.
This confirmed the root cause: the previously fitted pump/motor unit was both the wrong version for this vehicle and had not been programmed after installation.
Coding the New Unit and Restoring Power Steering on This VW Polo
With the root cause confirmed, we explained the findings to Mr H and outlined the steps required to complete the repair. Once authorised, we proceeded with the work.
- We sourced the correct pump/motor unit by referencing the vehicle’s VIN against Volkswagen’s parts database
- We inspected the electrical terminals, hydraulic lines, and harness routing to confirm there was no damage, wear, or obstruction
- The incompatible unit was removed, and the correct, vehicle-matched pump/motor was installed in its place
- All wiring and hydraulic connections were resecured, and the system was bled to remove any air
Once installation was complete, we moved on to the configuration stage.
- Using ODIS, Volkswagen’s official diagnostic platform, we accessed the steering control module
- We programmed the new unit to the vehicle, allowing it to communicate with the rest of the system
- We then cleared the stored fault code and completed a final system check
The steering warning light was no longer present on the dashboard, and power assistance returned during the post-repair test drive. The vehicle performed normally, with no further faults reported.
From Warning Light to Full Function: VW Polo Power Steering Fault Fixed
With the issue resolved and all systems functioning as intended, the VW Polo was back to safe and predictable steering. No warning lights remained, and the vehicle was ready to return to the road.
The result showed the value of a structured diagnostic process, supported by the right data, tools, and technical skills. By methodically identifying the cause of the fault, we were able to apply the correct repair with confidence.
Although the vehicle had already undergone a previous attempt at repair, the issue was resolved here in a single visit through evidence-based testing and accurate part matching.
Mr H left with confidence that the fault had been identified and professionally resolved. The repair was backed by our 12-month parts and labour guarantee, offering additional peace of mind.
Power Steering Not Working? Get Your VW Assessed by the Experts
If your VW Polo has a steering warning light illuminated or the steering has suddenly gone heavy, it’s time to get the system checked. Power steering faults can affect control and safety, and they don’t resolve on their own.
At Cole & Miller Automotives in Arlesey, we carry out detailed technical evaluations to identify the cause of steering issues and recommend the right solution. From sensor faults to incorrect part configuration, we trace the fault using verified procedures and test data.
Why Bedfordshire drivers trust us for VW power steering repair:
- Our technicians use Volkswagen diagnostic systems and manufacturer guidance
- We assess faults methodically to pinpoint the cause and prevent unnecessary work
- Every repair comes with a 12-month parts and labour guarantee
- Courtesy cars are available to keep you mobile during the repair
Join the {{review-count}} local drivers who rate Cole & Miller Automotives {{average-rating}} stars on Google for diagnostic-led repairs.
Call 01462 730803 to book your technical evaluation.
