BYD P20PS, Operator'S Manual

MAINTENANCE

OPERATOR MANUAL

39

P20PS

40

OM-P20PS2019001-EN

02A77

CONTACTOR OPEN

Contactor does not 

engage

The coil of main contactor has been energized by the logic card, but the contactor does not 

engage. Possible cause:

1.The contactor has mechanically become faulty, or its contacts get stuck.

2.The contacts of contactor cannot make securely.

3.If the contactor operates normally, replace the controller.

02A52 PUMP I=0 EVER

Oil pump I=0 fault

Check whether the power supply line of the oil pump motor is in good condition. If the line is 

in good condition, replace the controller;

02A53 STBY I HIGH

Standby current is high

The micro controller system has detected that the signal of the current sensor is outside 

the permissible range of current with the forklift in the idling state.  This fault is irrelevant to 

external components. Replace the controller.

02A60 CAPACITOR CHARGE

Capacitor charging 

error

With the key switch turned to “ON”, the controller will charge the capacitor via the power 

resistor. The controller will detect whether the capacitor is fully charged within the specified 

time. If the capacitor is not fully charged within the specified time, and the capacitor voltage 

is still less than 20% the battery voltage, the controller will display the warning and the main 

contactor will not engage.

Possible causes:

1.The charge process of the controller is interfered by external devices (for example, DC-DC 

converter and motor) or other devices. It is necessary to remove the interferences by these 

devices.

2.The power resistor is disconnected. The charge circuit or power supply module becomes

faulty. In these cases, replace the controller.

02A62 TH. PROTECTION

Controller over-temperature 

protection

Lower the controller temperature to below 85oC. If the fault still exists, possibly the 

temperature sensor or controller becomes faulty. Replace the controller.

02A65 MOTOR TEMPERAT

MOTOR TEMPERAT

Check whether U/V/W phase is correctly connected.

02A0

BATTERY LOW   

Battery level low

If the parameter “BATTERY CHECK” is not set to zero, no LED representing battery state-

of-charge will come on when battery state-of-charge is less than 15%. The warning will 

be displayed and the lift function of the forklift will be disabled. In this case, it is imperative 

to charge the battery. If the battery is operational, check whether the controller parameter 

“ADJUST BATTERY” agrees with the battery voltage.

02A74 DRIVER SHORTED   

Short circuit of drive

With the key switch turned to “ON”, the controller will check the drive of main contactor for 

short circuit. In case of short circuit, the warning will be displayed. Check whether the positive 

terminal of coil of main contractor is short circuited to A16 or negative terminal of power 

supply. If externality is normal, replace the controller.

02A75 CONTACTOR DRIVER 

Short circuit of drive

With the key switch turned to “ON”, the microprocessor will check the drive of main contactor 

for short circuit. In case of short circuit, the warning will be displayed. Check whether the 

positive terminal of coil of main contractor is short circuited to A16 or negative terminal of 

power supply. If externality is normal, replace the controller.

02A78 VACC NOT OK

Accelerator fault

Inspection time: With the forklift idling, the accelerator voltage is at least 1V higher than the 

minimum set in the “PROGRAM VACC” menu for accelerator signal range.

Possible causes:

1.Upper and lower limits of accelerator voltage are not taken. Move to the PRPGRAM VACC 

menu to take the limits again.

2.Accelerator error. Possible cause is that accelerator pedal failure to return to original

position, or internal error of accelerator.

3.Controller fault.

02A79 INCORRECT START

Startup sequence fault

Incorrect startup sequence. Possible causes:

1.The direction switch has already been turned on before the motor is turned on.

2.Operation sequence error.

3.Incorrect wiring connection.

4.If the fault cannot be eliminated, replace the controller.

02A80 FORW + BACK  

F o r w a r d   a n d   r e v e r s e 

signals exist at the same 

time  (direction  switch  gets    

stuck)

The controller can keep checking for this fault. Having detected that request signals in the two 

directions occur at the same time, the controller will issue a warning.

Possible causes:

1.Wire damaged.

2.Direction switch fault.

3.Improper operation.

4.If the fault cannot be eliminated, replace the controller.

02A82 ENCODER ERROR

Encoder fault

The controller detects that two successive speed readings of the encoder differs greatly from 

each other. A normal encoder in the system cannot change speed readings greatly within a 

very short time. Hence, a possible cause for the symptom is that the wires of one or more 

encoders are worn or broken. Check the mechanical and electrical parts of the encoder. 

Another possible for the symptom is electromagnetic interference from the sensor bearing

. If the symptom is not due to the two causes, replace the controller.

Note: Sometimes manual operations may also cause this fault indicating on the controller. In 

these cases, it is required to turn off power supply and start the forklift again. For example:

1.The forklift suddenly collides with an obstacle so that it is incapable of travelling;

2.The driver applies the brake sharply while the forklift is travelling at a high speed.

02A86 PEDAL WIRE KO

Fault with connection of 

positive and negative 

terminals of accelerator

Check whether the positive and negative terminals of the accelerator have been connected to 

the controller;

02A84 CAN BUS KO BMS

CAN BUS KO BMS

Check whether the BMS communication line operates normally.

02A21 CHARGE SAFETY

Charge safety

This fault can be reported if the forklift is operated while the battery is being charged. This 

prevents anyone from operating the forklift while the battery is being charged.

02A22 HEIGHT SENS LOCK
02A20 HEIGHT SENS OPEN

02A11 STALL ROTOR

Motor stalling

1.Motor stops running.

2.Motor encoder fault

3.Damaged harness or incorrect wiring connection.

4.Problem with power supply to the encoder.

02A71  HANDBRAKE  
02A78 BACKING INPUT

02A10 WRONG  RAM 

Fault with the dynamic 

memory

The fault is detected when the main memory is tested. Registered address is “DIRTY”. This 

fault can limit the operability of the forklift.

Fault analysis: Turn the key switch to “OFF”, then to “ON”. If the fault still exists, replace the 

controller.

02A74 AUX BATT. SHORT.

Fault with auxiliary drive 

voltage

Check whether BI is correctly connected to B5. If so, replace the controller;

02A50 EVP1 COIL OPEN

Open circuit of NAUX1 coil Check NAUX1 coil for open circuit, and whether EVP1 type setting is correct.

02A51 EVP2 COIL OPEN

Open circuit of NAUX2 coil Check NAUX2 coil for open circuit, and whether EVP2 type setting is correct.

02A79 WRONG STEER PAR.
02A56 PUMP I NO ZERO 

Current exceeds limit while 

pump motor does not run

Replace the controller;

02A67 SENS MOT TEMP KO

Temperature sensor fault

Symptom: Output signal of motor temperature sensor is outside the permissible range.

Solution: Check the signal value and connection of the sensor. If they are normal, the fault 

occurred in the controller.

02A98 DEAD MAN ABSENT

02A76 KEY OFF SHORTED 

Short circuit of the key 

switch

In the startup phase, if the controller detects a low logic level when the key switch is turned to 

“OFF”, this fault will be displayed.

Fault analysis: A highly possible cause is voltage being too low. Perform the following checks.

-Key switch based external load (for example, turning on the DC-DC converter. Relay or 

contactor switch input signal lower than startup voltage).

-Check the connections of the power supply cables to the positive and negative terminals 

of the battery, and to the terminals -BATT and + BATT terminals of the main contactor and 

controller. The screws shall be tightened to torque 13Nm to 15Nm.

-If no voltage drop in the power supply circuit is detected, this fault will be reported each 

time the key switch is turned to “ON”. The hardware of controller could become faulty. It is 

necessary to replace the controller.

02A8

FLASH CHECKSUM

Flash memory fault

With the key switch turned to “ON”, the value stored in the flash memory by the program 

should be a positive value. This fault will be reported in the case of a negative value.

Fault analysis: The flash memory of the microcontroller could become faulty. The flash 

memory, or the program stored could be damaged. Attempt to configure the program of the 

logic card again. If the fault is still there, it exists in the microcontroller. Replace the controller.

02A68 SMARTDRIVER KO

Drive of electromagnetic 

brake fault

Check whether the high end (CNB#1) of the drive of electromagnetic brake is short circuited 

to the terminal B-. If not, the internal drive module could be damaged.

02A76 COIL SHOR. MC-EB

M a i n   c o n t a c t o r   o r 

electromagnetic brake is 

heavily loaded

1.Check whether the output and load of the controller are excessive;

2.Replace the controller;

02A68 WAITING FOR NODE

Waiting for signal from a 

node

In the CAN communication network, a certain controller has received the signal that another 

controller cannot communicate normally. The said certain controller hence remains waiting 

until the whole CAN communication network reverts to normality. Check the controller that 

cannot communicate normally for failed connection. Check whether the software version or 

parameter settings are correct.

02A26 CURRENT SENS. KO

02A85 VACC OUT RANGE

Accelerator input is outside 

the permissible range.

1.Upper and lower limits of accelerator voltage are not correctly taken. Move to the

PRPGRAM VACC menu to take the limits again;

2.Check whether the accelerator connection is correct;

02A0

EPS RELE OPEN

02A51 TILLER OPEN

Ti l l e r   i n p u t   s w i t c h   i s 

disconnected

With the tiller input switch disconnected, after a period approximately 30s has elapsed, the 

main contactor will disengage and the warning will occur. The warning will not occur next time 

the forklift is operated.