Engine-Codes - Generic - P0888

P0888 - Transmission Relay Always Off

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3  What is this?
Table of contents

P0888 Possible Causes

  • Transmission Control Relay harness is open or shorted
  • Transmission Control Relay circuit poor electrical connection
  • Faulty Transmission Control Relay

How is the P0888 code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

What is the cost to diagnose the P0888 code

Labor: 1.0

The cost to diagnose the P0888 code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.
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When is the code detected?

This code is set when less than 3 volts are present at the Transmission Control Relay Output (switched battery) terminals at the Powertrain Control Module (PCM), when the PCM is energizing the relay.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P0888 Meaning

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.

More Information

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Information for specific makes

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