AutoCodes – Generic – P1002

P1002 Code - Ignition Key Off Timer Performance Too Slow

Quick Answer

The Transmission Control Module (TCM) uses ignition off time to enable other diagnostic tests. Common causes include Faulty Ignition Switch, Ignition Switch harness is open or shorted, Ignition 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: P1002 indicates Ignition Key Off Timer Performance Too Slow.
Common causes: Common causes include Faulty Ignition Switch, Ignition Switch harness is open or shorted, Ignition 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 14,170

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 13, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1002 Description

The Transmission Control Module (TCM) uses ignition off time to enable other diagnostic tests. The TCM must verify the proper operation of the ignition off timer to ensure the diagnostic tests are performed within the proper enable conditions. The ignition off timer value is stored in the Cabin Compartment Node (CCN). The CCN will send the ignition off time message to the Totally Integrated Power Module (TIPM). The TIPM broadcasts the ignition off time over the CAN bus. The TCM receives the message and then compares the ignition off timer value to the Engine Coolant Ignition off temperature and the Engine Coolant Start-up Temperature message. The Diagnostic Trouble Code (DTC) will set if the ignition off time is less than a calibrated value based on Engine Coolant Ignition off Temperature and the Engine Coolant Start-up Temperature.

OBDII Code P1002 - Ignition Key Off Timer Performance Too Slow - AutoCodes.com — P1002 Code - Ignition Key Off Timer Performance Too Slow

What does this mean?

What are the Possible Causes of the DTC P1002?

Faulty Ignition Switch
Ignition Switch harness is open or shorted
Ignition Switch circuit poor electrical connection
Faulty Cabin Compartment Node (CCN)

How to Fix the DTC P1002?

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 P1002 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

P1002 Buick — Fuel Pump Driver Control Module System Voltage Performance
P1002 Cadillac — Fuel Pump Driver Control Module System Voltage Performance
P1002 Chevrolet — Fuel Pump Driver Control Module System Voltage Performance
P1002 Chrysler — Ignition Key Off Timer Performance Too Slow
P1002 Dodge — Ignition Key Off Timer Performance Too Slow
P1002 GMC — Fuel Pump Driver Control Module System Voltage Performance
P1002 Jeep — Ignition Key Off Timer Performance Too Slow
P1002 Saab — Evaporative Emission Canister Purge Valve High Output

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.