HELP bike is throwing codes

[NicholasRocket92]

2022 Rocket 3 GT Drove it to work and parked it. Went to start it and it's having a really hard time turning on although I got it to wake up twice and start. Never done this before. Thowing 3 codes. Got any ideas what's going on?

 

[atomsplitter]

What's your battery voltage?

 

[NicholasRocket92]

V

What's your battery voltage?

Oltage is normal. 12.4v not running. 14.2v running.

 

[atomsplitter]

You cleared the DTC's and they came back?

 

[atomsplitter]

Looked up in the shop manual:
P1640- Roll Over detection disabled due to Inertial Measurement Unit (IMU) malfunction

P1695 - CAN fault - lost communication with instrument panel

P16A2 - Engine ECM detects IMU present but with signal error

It points to the IMU having a problem. If the fault is cleared after 40 start cycles the MIL light will clear or just use TuneECU and clear them and see if they come back.

Shop Manual Instructions:
Make sure ABS modulator connector is secure. Check for associated DTC C1713, perform tests for this DTC. Reset DTCs, if problem persists contact Triumph service.

Description of system:
IMU (if fitted) The Inertial Measurement Unit measures the following:
• Longitudinal acceleration
• Vertical acceleration
• Lateral acceleration
• Pitch rate
• Yaw rate
• Roll rate

From these measurements the IMU calculates the motorcycle's lean angle. The IMU outputs are used for multiple systems, for example, optimised cornering ABS (OCABS) and fall detection. If the IMU is fitted, the fall detection switch will not be fitted.

Here Comes the Bad News:
On the Rocket 3, the IMU is mounted on the frame (typically under the tank or near the ABS modulator). Replacement involves:

1. Remove bodywork to access the IMU​

Usually:

• Seat off
• Tank lifted or removed
• Side panels off

The IMU is a small rectangular sensor with a single multi‑pin connector.

2. Disconnect the IMU harness​

Triumph uses locking connectors — depress the tab and slide the connector out.The manual specifically tells you to verify the ABS modulator connector is secure when diagnosing IMU faults , because the IMU shares CAN communication paths.

3. Unbolt the IMU​

It’s mounted with 2–3 small bolts.Important: The IMU must be mounted perfectly level. Triumph uses fixed mounting points so alignment is automatic.

4. Install the new IMU​

Bolt it in, reconnect the harness.

5. Clear DTCs and verify communication​

The manual says:

• Clear DTCs
• If the problem persists, contact Triumph service

This is because the IMU is part of the CAN network, and the ECM must detect it and validate its signals.

6. Perform IMU calibration (dealer tool only)​

Triumph’s diagnostic system (Triumph OBD/DealerTool) performs:

• IMU initialization
• Zero‑angle calibration
• CAN handshake

TuneECU cannot perform IMU calibration — it can only clear codes.

Your current tab shows the IMU‑related fault codes:

• P1640 – Roll‑over detection disabled due to IMU malfunction
• P1695 – CAN fault, lost communication with instrument panel
• P16A2 – ECM detects IMU present but with signal error

These codes strongly suggest:

• Either the IMU is unplugged, water‑damaged, or internally failed
• Or the CAN line between IMU → ABS modulator → ECM is compromised

Because the IMU is part of the safety system (cornering ABS), Triumph requires calibration after replacement.

Here's The Good News:

Before replacing the IMU, check these first​

These are directly from the manual:

• Check ABS modulator connector (IMU shares CAN path)
• Check for DTC C1713 (ABS/IMU communication fault)
• Clear DTCs and see if they return

A loose ABS connector is far more common than a failed IMU.