U0402Network Communication

Invalid Data Received From TCM

U0402 means a module received invalid or implausible data from the transmission control module over the CAN bus. It can stem from a failing sensor, a software issue, or a wiring problem affecting the TCM's data.

🚗 Not recommended. Invalid data from the transmission computer can cause harsh shifts or limp mode.

HIGH

severity

🎯 Top Causes, Ranked by Likelihood

#1Underlying TCM sensor or transmission fault$100-$700

40%

A fault in the TCM's inputs produces invalid data on the bus.

#2Wiring or connector fault$50-$500

30%

Bus wiring problems corrupt the data being sent.

#3Software or module fault$100-$1500

20%

Outdated software or a failing TCM sends bad data.

🩺 Common Symptoms

Harsh or erratic shifting
Transmission limp mode
Multiple warning lights
Other U-codes and P-codes stored
Erratic gauges

💰 Repair Cost: DIY vs Shop

DIY Cost

$50-$400

Shop Cost

$150-$1000

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose U0402

1Scan for stored P-codes at the TCM first and address them

2Inspect CAN wiring and connectors for faults

3Check for TCM software updates

4Verify the TCM's sensor inputs read plausibly

❓ Frequently Asked Questions

Can I drive with U0402?

Not recommended. Invalid transmission data can cause harsh shifts or limp mode. Diagnose it first.

What causes U0402?

Often an underlying TCM fault or sensor problem producing bad data, or wiring issues on the bus.

Should I fix other codes first with U0402?

Yes. Address transmission P-codes at the TCM first, since they often cause the invalid data this code reports.

🔗 Related Codes

U0100U0401U0101U0300