AutoCodes – Jeep – P0888 Jeep

P0888 Jeep Code - Transmission Relay Always Off

Quick Answer

The transmission control relay is used to supply power to the solenoid pack when the transmission is in normal operating mode. Common causes include Faulty Transmission Control Relay, Transmission Control Relay harness is open or shorted, Transmission Control Relay 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: P0888 Jeep indicates Transmission Relay Always Off.
Common causes: Common causes include Faulty Transmission Control Relay, Transmission Control Relay harness is open or shorted, Transmission Control Relay 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 19,198

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 May 11, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P0888 Jeep Description

The transmission control relay is used to supply power to the solenoid pack when the transmission is in normal operating mode. When the relay is off, no power is supplied to the solenoid pack and the transmission is in Limp-in mode. The relay output is fed back to the Powertrain Control Module (PCM). It is referred to as the Transmission Control Relay Output circuit or switched battery.
After a controller reset (ignition key turned to the run position or after cranking engine), the controller energizes the relay. Prior to this the PCM verifies that the contacts are open by checking for no voltage at the switched battery terminals. After the relay is energized, the PCM monitors the terminals to verify that the voltage is greater than 3 volts.

OBDII Code P0888 Jeep - Transmission Relay Always Off - AutoCodes.com — P0888 Jeep Code - Transmission Relay Always Off

What does this mean?

What are the Possible Causes of the DTC P0888 Jeep?

Faulty Transmission Control Relay
Transmission Control Relay harness is open or shorted
Transmission Control Relay circuit poor electrical connection
Faulty Transmission Solenoid/Pressure Switch Assembly

How to Fix the DTC P0888 Jeep?

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 does this mean?

Code Tech Notes

Inadequate Transmission Control Relay Output voltage can also cause DTCs P0846, P0869, P0871, P0876 or P0988 to set. This does not indicate an internal transmission or solenoid TRS problem. Repairing the P0888 fault should also eliminate the related DTCs.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0888 Jeep 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.