AutoCodes – Cadillac – P0843 Cadillac

P0843 Cadillac Code - Transmission Fluid Pressure Switch 1 Circuit High Voltage

Quick Answer

The Transmission Fluid Pressure (TFP) switch 1 is part of the control solenoid valve assembly, which has no serviceable parts. Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Transmission Control Solenoid Valve Assembly. 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: P0843 Cadillac indicates Transmission Fluid Pressure Switch 1 Circuit High Voltage.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Transmission Control Solenoid Valve Assembly.
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 494

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 02, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0843 Cadillac Description

The Transmission Fluid Pressure (TFP) switch 1 is part of the control solenoid valve assembly, which has no serviceable parts. The Transmission Control Module (TCM) supplies a signal circuit to the TFP Switch 1. The TFP Switch 1 has an internal case ground. TFP Switch 1 is normally closed or LOW. When oil pressure is present at the TFP Switch 1, the switch is open or HIGH. The normally high clutch pressure control (PC) solenoid 2 controls pressure to the 3-5 reverse clutch regulator valve. The TCM monitors the TFP switch 1 to determine the position of the 3-5 reverse clutch regulator valve. When the 3-5 reverse clutch is commanded OFF, pressure is present on the TFP switch 1. When the 3-5 reverse clutch is commanded ON, the 3-5 reverse clutch regulator valve moves and pressure to the TFP switch 1 is exhausted through the 3-5 reverse clutch regulator valve. The Diagnostic Trouble Code (DTC) will be set when the TCM detects that the TFP switch 1 signal voltage remains HIGH after the 3-5-R clutch transitions from a LOW pressure state to a HIGH pressure state. The TCM counts each incident. The DTC sets when 35 counts are accumulated.

OBDII Code P0843 Cadillac - Transmission Fluid Pressure Switch 1 Circuit High Voltage - AutoCodes.com — P0843 Cadillac Code - Transmission Fluid Pressure Switch 1 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0843 Cadillac?

Low transmission fluid level
Dirty transmission fluid
Faulty Transmission Control Solenoid Valve Assembly
Transmission Control Solenoid Valve Assembly harness is open or shorted
Transmission Control Solenoid Valve Assembly circuit poor electrical connection

How to Fix the DTC P0843 Cadillac?

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 P0843 Cadillac 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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Get the P0843 Cadillac code diagnosed by a professional: Find a repair shop in your area

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 P0843 Cadillac Code

1. What are common symptoms of OBDII code P0843 in a Cadillac?

Common symptoms may include harsh shifting, transmission slipping, transmission overheating, and illuminated warning lights on the dashboard.

2. What can cause the OBDII code P0843 in a Cadillac?

The code P0843 is typically triggered by a faulty transmission fluid pressure switch, damaged wiring or connectors related to the switch, low transmission fluid levels, or a malfunctioning transmission control module.

3. How serious is the OBDII code P0843 in a Cadillac?

Ignoring the code P0843 can lead to further damage to the transmission system, potentially resulting in expensive repairs. It is recommended to address this issue promptly to prevent more significant issues.

4. Can I continue driving my Cadillac with the OBDII code P0843?

It is not advisable to continue driving your Cadillac with the code P0843 present, as it can cause further damage to the transmission. It is recommended to have the issue diagnosed and repaired as soon as possible.

5. How is the OBDII code P0843 diagnosed in a Cadillac?

Diagnosing the code P0843 typically involves using a diagnostic scanner to retrieve the specific fault code, conducting a visual inspection of the transmission fluid pressure switch and related components, and testing the switch for proper operation.

6. How is the OBDII code P0843 repaired in a Cadillac?

Repairing the code P0843 may involve replacing the transmission fluid pressure switch, repairing or replacing damaged wiring or connectors, ensuring proper transmission fluid levels, and resetting the fault codes with a diagnostic scanner.

7. Can a DIY enthusiast repair the OBDII code P0843 in a Cadillac?

While some DIY enthusiasts may have the skills to address the code P0843, it is recommended to consult a professional mechanic or technician for proper diagnosis and repair to ensure the issue is resolved correctly.

8. How much does it cost to repair the OBDII code P0843 in a Cadillac?

The cost of repairing the code P0843 can vary depending on the specific cause of the issue, labor rates in your area, and whether any parts need to be replaced. It is advisable to obtain quotes from different repair shops for an accurate estimate.

9. How can I prevent the OBDII code P0843 from occurring in my Cadillac?

Regular maintenance of your Cadillac, including checking transmission fluid levels, addressing any fluid leaks promptly, and ensuring timely transmission inspections, can help prevent issues like the code P0843 from occurring.

10. Is the OBDII code P0843 covered under Cadillac's warranty?

If your Cadillac is still under warranty, the repair for the OBDII code P0843 may be covered, depending on the specific terms of the warranty. It is recommended to check with your dealership or refer to your warranty documentation for more information.