P171D Code - Transmission Fluid Pressure Accumulator System Performance
Quick Answer
The Automatic Transmission Auxiliary Fluid Accumulator is used to provide transmission fluid line pressure to the transmission during an autostart event. Common causes include Faulty Transmission Fluid Pressure Accumulator, Transmission Fluid Pressure Accumulator harness is open or shorted, Transmission Fluid Pressure Accumulator circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P171D indicates Transmission Fluid Pressure Accumulator System Performance.
- Common causes
- Common causes include Faulty Transmission Fluid Pressure Accumulator, Transmission Fluid Pressure Accumulator harness is open or shorted, Transmission Fluid Pressure Accumulator circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P171D Description
When the engine is shut off during an autostop event, there is no transmission line pressure. During an autostart event, the Hybrid/EV Powertrain Control Module 1 commands the Automatic Transmission Auxiliary Fluid Accumulator solenoid valve on, allowing transmission fluid to discharge from the accumulator, supplying line pressure to the transmission. The accumulator will start to recharge when the transmission fluid pump increases line pressure higher than accumulator pressure. Transmission fluid will flow through the solenoid valve until the Hybrid/EV Powertrain Control Module 1 turns the solenoid off and also flow through a check valve.
The Hybrid/EV Powertrain Control Module 1 monitors clutch slip during an autostart event. The DTC will set if the Hybrid/EV Powertrain Control Module 1 detects that the accumulator system is not capable of supplying adequate pressure during autostart.
Hybrid/EV Powertrain Control Module 1 detects excessive transmission slip during an autostart. This must occur 15 times, with 3 of the times on separate autostart events.
What are the Possible Causes of the DTC P171D?
- Faulty Transmission Fluid Pressure Accumulator
- Transmission Fluid Pressure Accumulator harness is open or shorted
- Transmission Fluid Pressure Accumulator circuit poor electrical connection
How to Fix the DTC P171D?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P171D code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific Makes
- P171D Buick — Transmission Fluid Pressure Accumulator System Performance
- P171D Cadillac — Transmission Fluid Pressure Accumulator System Performance
- P171D Chevrolet — Transmission Fluid Pressure Accumulator System Performance
- P171D GMC — Transmission Fluid Pressure Accumulator System Performance
Frequently Asked Questions about P171D Code
1. What are the common symptoms of OBDII code P171D (Transmission Fluid Pressure Accumulator System Performance)?
- Common symptoms include harsh shifting, transmission slipping, poor acceleration, and potential transmission overheating.
2. What can cause OBDII code P171D to trigger?
- The code may be triggered by issues such as low transmission fluid levels, a faulty transmission pressure control solenoid, a clogged transmission filter, or a failing transmission pump.
3. How serious is OBDII code P171D (Transmission Fluid Pressure Accumulator System Performance)?
- This code can indicate potential issues with the transmission system that, if left unresolved, may lead to further damage and costly repairs. It is recommended to address the underlying problem promptly.
4. What are some DIY repair tips for OBDII code P171D?
- DIY repair tips may include checking and topping up transmission fluid levels, inspecting for any leaks, ensuring proper fluid quality, and performing a transmission fluid flush if necessary.
5. Can driving with OBDII code P171D (Transmission Fluid Pressure Accumulator System Performance) cause further damage?
- Continuing to drive with this code present can potentially lead to more severe transmission problems, such as gear slippage, total transmission failure, or damage to internal components.
6. How can a mechanic diagnose OBDII code P171D?
- A mechanic can diagnose this code using a professional OBDII scanner to read the code and further inspect the transmission system for issues like fluid leaks, pressure control solenoid functionality, and overall transmission health.
7. Is it safe to reset the OBDII code P171D without addressing the underlying issue?
- Resetting the code without fixing the underlying problem is not recommended, as it will not resolve the root cause and may lead to ongoing transmission issues.
8. How much does it typically cost to repair OBDII code P171D?
- The cost of repairing this code can vary depending on the specific issue causing it. Repairs may range from relatively inexpensive tasks like fluid top-ups to more costly repairs involving transmission component replacement.
9. Can regular maintenance help prevent OBDII code P171D from occurring?
- Regular maintenance, such as routine transmission fluid changes, can help prevent issues that may trigger this code. Following the manufacturer's maintenance schedule is crucial for transmission health.
10. What are the long-term consequences of ignoring OBDII code P171D?
- Ignoring this code can lead to progressive damage to the transmission system, potentially resulting in complete transmission failure and the need for a costly replacement. Addressing the issue promptly is essential to prevent further damage.
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