Discovery 2. Manual - part 147

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

AUTOMATIC GEARBOX - ZF4HP22 - 24

44-20

DESCRIPTION AND OPERATION

P1613

(1)

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

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

On

On

P1705

(39)

Transmission high/low 
range, implausible 
input

No apparent effect

On

Off

P1810

(12, 13)

Sport/Manual warning 
lamp circuit fault

Lamp fails bulb check or is permanently 
illuminated. No effect on gearbox operation.

On

Off

P1841

(16)

* CAN bus fault

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

On

On

P1842

(15)

* CAN level monitoring

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

On

On

P1843

(17)

* CAN time-out 
monitoring

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

On

On

P1884
(11)

* CAN message: 
Engine friction invalid

No apparent effect.

On

Off

P1884
(18)

* CAN message: 
Throttle position invalid

Substitute throttle angle of 50% adopted. No 
kickdown. Operates in economy modes only.

On

On

P1884
(19)

CAN message: Engine 
temperature invalid

Substitute engine temperature derived from 
other inputs. No apparent effect.

On

Off

P1884
(20)

CAN message: Road 
speed invalid

No apparent effect

On 

Off

P1884
(33, 34)

* CAN message: 
Engine torque invalid

Substitute engine torque of derived from other 
inputs. May affect shift quality.

On

Off

P1884
(35)

* CAN message: 
Engine speed invalid

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

On

On

P1884
(37)

CAN message: Engine 
air intake temperature 
invalid

No apparent effect.

On

Off

P1844

(38)

Altitude shift control 
invalid

No reduced torque compensation, possible 
reduction in performance/ driveability at 
altitude or high ambient temperatures.

On

Off

* = Emissions (OBD II) relevant
†On = MIL illuminates immediately (in all other faults, MIL On = illuminates in the 2nd consecutive drive cycle if 
fault still present)

Fault code, 

OBD II 

(TestBook)

Fault description

Effect

Warning lamp 

illumination

MIL

Sport/ 

Manual

AUTOMATIC GEARBOX - ZF4HP22 - 24

ADJUSTMENTS

44-21

ADJUSTMENTS

Cable - selector  

$% 44.30.04 

Check

1. Position vehicle on ramp. 
2. Select position 'P'. 

3. Loosen selector cable trunnion nut. 
4. Ensure that gearbox selector lever is in  'P' 

position, (fully forward) and tighten  trunnion 
nut. 

5. Lower ramp. 

Stall test

$% 44.30.13

Testing

1. Chock the wheels and fully apply the 

handbrake.

2. Start the engine and run it until it reaches 

normal operating temperature.

3. Apply the footbrake and select 'D'.
4. Fully depress the accelerator pedal and note 

the tachometer reading. The figures should be 
as given below. Do not carry out stall test for 
longer than 10 seconds, and DO NOT repeat 
until 30 minutes have elapsed.

l

V8:  2200 to 2400 rev/min

l

Diesel:  2600 to 2800 rev/min

5. A reading below 1300 rev/min indicates a 

torque converter fault, ie stator free-wheel.

6. A reading between 1300 and 2200 rev/min (V8) 

or between 1300 and 2600 rev/min (Diesel) 
indicates reduced engine power.

7. A reading above 2400 rev/min (V8) or above 

2800 rev/min (Diesel) indicates clutch slip.

NOTE: The figures quoted above were 
measured at sea level with an ambient 
temperature of 20

°

C (68

°

F). At higher altitudes 

or higher ambient temperatures, these figures 
will be reduced.