AUTOMATIC GEARBOX - ZF4HP22 - 24: DESCRIPTION AND OPERATION (page 3 of 4)

AUTOMATIC GEARBOX - ZF4HP22 - 24

DESCRIPTION AND OPERATION

44-19

Fault effects and warning indications

Fault code, 

OBD II 

(TestBook)

Fault description

Effect

Warning lamp 

illumination

MIL

Sport/ 

Manual

P0705

(14, 23)

* Gear position switch, 
incorrect outputs

Maintains current gear in low range, limp 
home mode in high range. Shift pressure to 
maximum, harsh gear shifts/engagement.

On On

P0721

(21)

* Downshift safety 
monitor prevented 
downshift which would 
have caused engine 
overspeed

Maintains current gear in low range, limp 
home mode in high range. Shift pressure to 
maximum, harsh gear shifts/engagement.

On

On

P0722

(22)

* Torque converter 
slipping

Maintains current gear in low range, limp 
home mode in high range. Shift pressure to 
maximum, harsh gear shifts/engagement.

On

On

P0731

(29)

* Ratio monitoring, 
implausible 1st gear 
ratio

No apparent effect

On

On

P0732

(30)

* Ratio monitoring, 
implausible 2nd gear 
ratio

No apparent effect

On

Off

P0733

(31)

* Ratio monitoring, 
implausible 3rd gear 
ratio

No apparent effect

On

Off

P0734

(32)

* Ratio monitoring, 
implausible 4th gear 
ratio

No apparent effect

On

Off

P0741

(5)

* Torque converter 
lock-up clutch fault

May affect driveability.

On

Off

P0743
(7, 25)

* Torque converter 
lock-up solenoid (MV 
3), open or short circuit

Limp home mode in low and high ranges. Shift 
pressure to maximum, harsh gear shifts/
engagement.

On

On

P0748

(10, 28)

* Pressure regulating 
solenoid (MV 4), open 
or short circuit

Limp home mode in low and high ranges. Shift 
pressure to maximum, harsh gear shifts/
engagement.

On

On

P0753
(8, 26)

* Shift solenoid (MV 1), 
open or short circuit

Limp home mode in low and high ranges. Shift 
pressure to maximum, harsh gear shifts/
engagement.

On

On

P0758
(9, 27)

* Shift solenoid (MV 2), 
open or short circuit

Limp home mode in low and high ranges. Shift 
pressure to maximum, harsh gear shifts/
engagement.

On

On

P1562

(24)

* Battery supply below 
9V while engine 
running

Maintains current gear in low range, limp 
home mode in range. Shift pressure to 
maximum, harsh gear shifts/engagement.

Off

On

P1601

(4)

* ECU, EEPROM 
checksum

Limp home mode in low and high ranges. Shift 
pressure to maximum, harsh gear shifts/
engagement.

On

On

P1606
(3)

* EEPROM

No apparent effect

On†

Off

P1606

(6)

* Watchdog

No apparent effect

On

On

P1612

(2)

* Solenoid valves 
power supply relay, 
sticking closed or open 
circuit

Limp home mode in low and high ranges. Shift 
pressure to maximum, harsh gear shifts/
engagement.

On

On