FANUC SYST-045 TP Enabled in AUTO Mode: Why the Cell Refuses to Run After You Swap the Pendant

You roll the cabinet back into AUTO, send the cycle-start from the PLC, and nothing happens. The pendant shows SYST-045 TP Enabled in AUTO Mode and the controller refuses every run request. The fix is one switch flick away, but the reason it keeps coming back is usually procedural, not electrical. At Probot Systems we see this on almost every commissioning where the integrator forgot to brief the line operator on the pendant rules.

This post is written for technicians and line operators dealing with SYST-045 on R-30iA, R-30iA Mate, R-30iB, and R-30iB Plus controllers. The behaviour is identical across the family. If you have a CRX with the tablet pendant, the symptom is the same but the toggle lives in a different menu.

What this error actually means

SYST-045 is the controller’s way of saying that you cannot have both AUTO mode and an active teach pendant at the same time. Per the FANUC R-30iB Plus error code manual: “The mode selector is in AUTO and the TP ON/OFF switch is in the ON position. Remedy: Turn the TP ON/OFF switch to OFF. Press RESET.” That is the entire definition.

On the shop floor, that quote translates as follows: when the mode key is in AUTO, the controller expects production input (UOP, PLC, cycle-start button) to drive the robot. When the teach pendant is enabled, the controller expects manual jog/teach input. These two control sources are mutually exclusive by FANUC safety design. The moment both are asserted, the controller blocks all run requests and posts SYST-045 until you pick one.

It is not a hardware fault. It is not a wiring issue. It is a configuration the operator has to clear with their hand on the pendant.

Most common causes, in order of probability

1. Teach pendant left in ON after a teach session. The most common case. Someone touched up a position in T1, walked back to the cabinet, turned the key to AUTO, and never flipped the TP switch back. The cycle-start fails and the screen shows SYST-045.
2. TP swap done with the switch still in ON. When a pendant is unplugged and a new one is plugged in with its ON/OFF switch in ON, SYST-045 can fire as soon as AUTO is selected. Boot order matters here.
3. Operator using the TP as a remote start. Some operators want to hold the pendant in their hand while AUTO runs, “just in case.” That is what the safety chain is explicitly designed to prevent.
4. Severity table modified by a previous integrator. SYST-045 can be raised from a pause to an abort via the error severity table. If you see it stop the program rather than just pause it, someone deliberately changed that (reference thread).
5. Cabinet vs. remote TP confusion on older R-30iA. A handful of cells have a panel-mounted TP and a cabinet TP. Confirm which one the controller is currently scanning.

How to diagnose in under 10 minutes

Step 1. Look at the teach pendant. The ON/OFF switch is on the top edge or left side, depending on iPendant model. If it is in ON, that is your problem (DIY Robotics community thread on SYST-045).

Step 2. Look at the cabinet mode key. AUTO position is the third detent on most R-30iB cabinets. If it is in T1 or T2, SYST-045 is not what you actually have, look at the alarm log again because the controller throws different alarms (SYST-026 family) when the relationship is reversed.

Step 3. Open the alarm log via MENU > 4 STATUS > Alarm. SYST-045 should be at the top. The alarm directly under it tells you what the operator was doing when the conflict was created.

Step 4. Check the error severity table under MENU > SETUP > Error Table. SYST-045 default severity is WARN/PAUSE. If it is set to ABORT, somebody upgraded it on purpose to force operators to confirm the state (same robot-forum thread).

Step 5. Confirm safety chain status under MENU > 4 STATUS > Safety Signals. Everything should be green. If a deadman or fence signal is flickering, the SYST-045 is downstream of a real safety event, not the cause.

How to fix it

For the routine case (TP left on after teaching):

1. Flip the TP ON/OFF switch to OFF.
2. Press RESET on the teach pendant.
3. Send the cycle-start from the PLC again.

That clears the alarm in under five seconds. The manual is explicit on this exact sequence and there is no parameter change required.

For the recurring case (operators keep doing it):

Modify the line procedure so the pendant is hung back in its cradle with the switch in OFF before the key is turned to AUTO. If you are running an unmanned cell, the pendant should normally stay in OFF anyway, only enabled when someone is at the cell to teach.

For the case where SYST-045 aborts the program instead of pausing:

The behaviour was changed in the error severity table on purpose. To revert: MENU > SETUP > Error Table, find SYST-045, change severity from ABORT to WARN (or PAUSE depending on what your shop standard is). Save and reset. The robot-forum discussion above shows why someone might want it to ABORT (forces operators to acknowledge the conflict), but most production cells run it as a warning.

For a CRX with the tablet pendant: the toggle is in the tablet safety menu, not a physical switch. Same logic, different button.

When to call a specialist

Two cases worth a service call rather than another reset:

The SYST-045 returns every time you cycle power, even with the TP switch verified OFF. That is not a procedural issue, it is a stuck TP enable contact or a faulty cable. Replacing the pendant or its cable will fix it. Confirm with a known-good TP before ordering parts.

You are commissioning a new cell with a UOP-driven start and want SYST-045 to never reach a line operator. There is a documented way to gate the AUTO mode entry through the PLC so the controller refuses to enter AUTO while the TP is enabled, which is the correct safety design and not what most field crews build by default.

contact us for a commissioning audit, or schedule a maintenance preventive visit so the pendant cabling and severity table are reviewed before a production batch.

Related errors to check

• SYST-026 (TP disabled in T1/T2): the mirror image. Mode key in T1 or T2 with the TP off, SVON on. Same dual-source conflict, opposite direction.
• SYST-212 (Need to apply to DCS param): pops up after parameter or mastering changes. Unrelated to the pendant switch but often seen in the same alarm log when commissioning is in progress.
• SRVO-007 / SRVO-218: not the same code family, but if SYST-045 is recurring with no operator action, the safety chain itself may be intermittent.

Probot Systems is a FANUC integrator based in Lévis, Quebec serving Canada and the US. If your operators are stopping the line on SYST-045 every shift, the fix is probably a procedure or a TP cable, and either one is a quick contact us conversation.