AutoCodesPontiac – P1816 Pontiac

P1816 Pontiac Code - Transmission Fluid Pressure Valve Position Switch-Park/Neutral With Drive Ratio

Quick Answer

The automatic Transmission Fluid Pressure (TFP) manual valve position switch consists of five pressure switches (two normally-closed and three normally-open) and a Transmission Fluid Temperature (TFT) sensor combined into one unit. Common causes include Faulty Automatic Transmission Fluid Pressure (TFP) Manual Valve Position Switch, TFP Valve Position Switch harness is open or shorted, TFP Valve Position Switch 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
P1816 Pontiac indicates Transmission Fluid Pressure Valve Position Switch-Park/Neutral With Drive Ratio.
Common causes
Common causes include Faulty Automatic Transmission Fluid Pressure (TFP) Manual Valve Position Switch, TFP Valve Position Switch harness is open or shorted, TFP Valve Position Switch 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.
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Code Popularity 2,429
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Sep 20, 2019
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Code P1816 Pontiac Description

The automatic Transmission Fluid Pressure (TFP) manual valve position switch consists of five pressure switches (two normally-closed and three normally-open) and a Transmission Fluid Temperature (TFT) sensor combined into one unit. The combined unit mounts on the valve body.
The Powertrain Control Module (PCM) supplies ignition voltage for each range signal. By grounding one or more of the circuits through various combinations of the pressure switches, the PCM detects which manual valve position you select. The PCM compares the actual voltage combination of the switches to a TFP manual valve position switch combination table stored in memory.
The TFP manual valve position switch cannot distinguish between PARK and NEUTRAL because the monitored valve body pressures are identical. With the engine OFF and the ignition switch in the RUN position, the TFP manual valve position switch indicates PARK or NEUTRAL. Disconnecting the AT inline 20-way connector removes the ground potential for the three range signals to the PCM. In this case, with the engine OFF, and the ignition switch in the RUN position, D2 will be indicated.
OBDII Code P1816 Pontiac - Transmission Fluid Pressure Valve Position Switch-Park/Neutral With Drive Ratio - AutoCodes.com
P1816 Pontiac Code - Transmission Fluid Pressure Valve Position Switch-Park/Neutral With Drive Ratio

What are the Possible Causes of the DTC P1816 Pontiac?

  • Faulty Automatic Transmission Fluid Pressure (TFP) Manual Valve Position Switch
  • TFP Valve Position Switch harness is open or shorted
  • TFP Valve Position Switch circuit poor electrical connection

How to Fix the DTC P1816 Pontiac?

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 P1816 Pontiac 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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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1816 Pontiac Code

1. What does the P1816 code mean on a Pontiac?

The P1816 code indicates an issue with the Transmission Fluid Pressure Valve Position (TFPVP) switch, specifically detecting an invalid park/neutral signal in relation to the drive ratio.

2. What are the symptoms of a P1816 code on a Pontiac?

Common symptoms include the Check Engine Light turning on, transmission slipping, difficulty shifting gears, or the vehicle being stuck in a specific gear.

3. What causes the P1816 code to appear on a Pontiac?

Possible causes include a faulty TFPVP switch, damaged wiring or connectors, low transmission fluid, or internal transmission issues.

4. How can I diagnose the P1816 code on my Pontiac?

Diagnosis involves using an OBDII scanner to confirm the code, inspecting the TFPVP switch and its wiring for damage, checking transmission fluid levels, and testing the transmission's internal components.

5. Can I drive my Pontiac with the P1816 code?

It’s not recommended to drive with this code, as it can lead to further transmission damage or unsafe driving conditions due to shifting problems.

6. How do you fix the P1816 code on a Pontiac?

Repairs may involve replacing the TFPVP switch, repairing damaged wiring or connectors, topping off or replacing the transmission fluid, or addressing internal transmission problems.

7. What is the TFPVP switch, and what does it do?

The TFPVP switch monitors the transmission fluid pressure and ensures the correct gear selection based on the vehicle’s operating conditions.

8. How much does it cost to repair the P1816 code on a Pontiac?

The cost varies depending on the specific issue but typically ranges from $100 to $500, including parts and labor.

9. Can low transmission fluid cause the P1816 code?

Yes, low transmission fluid can lead to incorrect pressure readings and trigger the P1816 code.

10. Is a professional mechanic necessary to fix the P1816 code on a Pontiac?

While some issues like checking fluid levels can be handled by a DIYer, diagnosing and repairing electrical or internal transmission problems is best left to a professional.

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