Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2010 Mazda 6 L4-2.5LFACTORY OEM SERVICE PROCEDURE
Engine Controls - Limp Home Mode/DTC P0600 Set
Bulletin No: 01-051/10
Last Issued: 10/15/10
SUBJECT: MIL ILLUMINATION - DTC P0600
BULLETIN NOTE
APPLICABLE MODEL(S)/VINS
DESCRIPTION
If the engine is started with a weak battery, some vehicles will store a DTC P0600 in memory and may go into "limp home" mode. In some cases other DTCs such as P2101, P0140, or P0571 may also be stored.
^ P0600: Serial communication link
NOTE:
^ "Limp home" mode is a driving mode in which the throttle valve opening amount is fixed in order to avoid a dangerous driving situation due to a PCM failure.
^ DTC P0600 cannot be erased unless the vehicle is out of "limp home" mode.
When battery voltage becomes too low, both PCM (main and sub) computers stop operating. When battery voltage returns to normal, the main computer restores itself, however, the sub computer does not. As a result, the main computer diagnoses the sub computer malfunction and allows a DTC P0600 to be stored in memory.
Customers having this concern should have their vehicle repaired using the following repair procedure.
REPAIR PROCEDURE
Restore PCM sub computer according to the following:
1. Verify customer concern.
2. Record customer's pre-set radio stations.
3. Disconnect negative battery cable.
4. Depress brake pedal for at least one (1) minute.
5. Diagnose battery to determine if battery needs to be replaced. If not, recharge battery.
6. Reconnect negative battery cable.
7. Clear DTC from PCM memory using M-MDS.
8. If DTC is still stored, troubleshoot it according to Workshop Manual.
9. Re-enter customer's pre-set radio stations.
10. Perform "Power Window Initialization" procedure to restore power window functions.
11. Verify repair.
Last Issued: 10/15/10
SUBJECT: MIL ILLUMINATION - DTC P0600
BULLETIN NOTE
APPLICABLE MODEL(S)/VINS
DESCRIPTION
If the engine is started with a weak battery, some vehicles will store a DTC P0600 in memory and may go into "limp home" mode. In some cases other DTCs such as P2101, P0140, or P0571 may also be stored.
^ P0600: Serial communication link
NOTE:
^ "Limp home" mode is a driving mode in which the throttle valve opening amount is fixed in order to avoid a dangerous driving situation due to a PCM failure.
^ DTC P0600 cannot be erased unless the vehicle is out of "limp home" mode.
When battery voltage becomes too low, both PCM (main and sub) computers stop operating. When battery voltage returns to normal, the main computer restores itself, however, the sub computer does not. As a result, the main computer diagnoses the sub computer malfunction and allows a DTC P0600 to be stored in memory.
Customers having this concern should have their vehicle repaired using the following repair procedure.
REPAIR PROCEDURE
Restore PCM sub computer according to the following:
1. Verify customer concern.
2. Record customer's pre-set radio stations.
3. Disconnect negative battery cable.
4. Depress brake pedal for at least one (1) minute.
5. Diagnose battery to determine if battery needs to be replaced. If not, recharge battery.
6. Reconnect negative battery cable.
7. Clear DTC from PCM memory using M-MDS.
8. If DTC is still stored, troubleshoot it according to Workshop Manual.
9. Re-enter customer's pre-set radio stations.
10. Perform "Power Window Initialization" procedure to restore power window functions.
11. Verify repair.
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.