JCB Excavator 657 Fault Code: Loss Of High Speed Tracking
Loss Of High Speed Tracking · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Fault code 657 on JCB excavators means the machine has lost high speed tracking, the fast travel mode used for moving between work areas. JCB directs technicians to test track motor speeds and pressure switches, and to confirm whether the 'hare' symbol displays when high speed is selected.
Medium severity. This is a travel performance fault, not an immediate safety or engine-damage event. The excavator can typically still move in low range, but reduced travel speed can slow down site work and may point to a developing hydraulic or electrical problem worth fixing before it worsens.
What does JCB Excavator error code 657 mean?
Fault code 657 indicates the excavator is not shifting into or maintaining its high speed tracking mode. High speed tracking is the faster of the two travel ranges on a two-speed track motor, controlled by a pilot pressure signal that shifts the motor from low gear (high torque) to high gear (high speed).
When this code sets, the operator may notice the machine only travels in low range, or that selecting high speed does not change travel speed at all. JCB ties the diagnosis directly to the track motor's speed change mechanism and the pressure switches that monitor or control that shift.
The 'hare' symbol referenced in the diagnostic steps is the operator display icon that normally lights up when high speed travel is active. Whether that icon appears or not is a key clue JCB uses to narrow down if the problem is electrical (signal/display) or hydraulic (actual gear change at the motor).
Common causes of 657
- Track motor not shifting speeds correctly, so the motor stays in low range even when high speed is requested
- Faulty or misadjusted pressure switch that fails to detect or signal the high gear pilot pressure
- Insufficient or missing pilot pressure at the port that shifts the track motor into high gear
- Wiring or display fault affecting the 'hare' symbol indication, separate from the actual mechanical shift
How to troubleshoot JCB Excavator 657: first checks
- Select high speed tracking and check whether the 'hare' symbol appears on the display. Note whether it shows or not, since this tells you if the issue is electrical/display-side or purely hydraulic.
- Test the track motor speeds directly to confirm whether the motor itself is actually changing from low to high range when commanded.
- Test the pressure switches associated with the high gear selection circuit to confirm they are switching correctly.
- With high speed tracking selected, check the pilot pressure at the port that shifts the track motor into high gear. Compare pressure between both tracks if only one side is affected.
- Inspect wiring and connectors to the pressure switches and any related solenoid for corrosion, looseness, or damage.
How the code clears
No reset procedure is listed for this code. Resolution depends on correcting whatever the checks reveal, whether that is a motor mechanical issue, a faulty pressure switch, or low pilot pressure, and confirming normal operation by re-selecting high speed tracking.
Frequently asked questions
What does JCB fault code 657 mean?
It means the excavator has lost high speed tracking, the fast travel range on the track motors. The machine may be stuck in low speed travel only.
Will the excavator still move with fault code 657 active?
Typically yes, in low range. The fault affects the high speed shift, not basic travel function, though this can vary by machine and the underlying cause.
How do I know if the problem is electrical or hydraulic?
Check whether the 'hare' symbol appears on the display when high speed is selected. If the symbol shows but the machine does not actually speed up, suspect the hydraulic side, such as low pilot pressure or a motor that is not shifting. If the symbol does not show at all, check wiring and the pressure switch circuit first.
What should a technician check first for code 657?
Start with the two tests JCB specifies: test the track motor speeds to see if the motor shifts ranges, and test the pressure switches for correct operation. Also check pilot pressure at the port that shifts the track motor into high gear.
Is fault code 657 an emergency?
No. It is a performance issue affecting travel speed, not an immediate safety or engine risk. However, reduced tracking speed should be diagnosed before continued heavy use, as it may indicate a developing hydraulic or switch problem.
Does fault code 657 affect one track or both?
It can affect either, depending on the cause. Comparing pilot pressure and motor speed test results between the left and right track motors helps isolate whether the fault is on one side or both.