Description (page 7 of 9)

ENGINE MANAGEMENT SYSTEM - SIEMENS

18-4-38 DESCRIPTION AND OPERATION

1671

ECM cooling fan signal

Short to battery

No

No

A

1672

Serial link with 

immobilisation ECU

Code implausible

No

No

A

1676

ECM, throttle monitoring/ self 

test

Engine torque versus driver 

demand implausible

No

Yes

B

1677

ECM, throttle monitoring/ self 

test

Engine speed versus driver 

demand implausible

No

No

B

1678

Throttle

Potentiometer 1 defective

Yes

Yes

B

1679

Throttle

Potentiometer 2 defective

Yes

Yes

B

1689

Brake vacuum enhancer 

solenoid valve – Up to 2003 

model year

Short circuit to battery

No

No

A

1690

Brake vacuum enhancer 

solenoid valve – Up to 2003 

model year

Short circuit to earth

No

No

A

1691

Brake vacuum enhancer 

solenoid valve – Up to 2003 

model year

Open circuit

No

No

A

1692

Main relay

Main relay fault

No

No

A

1697

Ambient pressure

Value not plausible

No

No

A

1698

Ambient pressure

Failure value stored

No

No

A

1699

Ambient pressure

Learning not successful

No

No

A

2122

APP sensor - Potentiometer 

1

Short circuit to earth or open 

circuit

Yes

Yes

A

2123

APP sensor - Potentiometer 

1

Short circuit to battery

Yes

Yes

A

2127

APP sensor - Potentiometer 

2

Short circuit to earth or open 

circuit

Yes

Yes

A

2128

APP sensor - Potentiometer 

2

Short circuit to battery

Yes

Yes

A

2138

APP sensor - Potentiometer 

comparison

Switch D/E voltage correlation

No

Yes

B

P Code No.

Component/Signal

Fault Description

Warning Lamp

Drive Cycle

SERVICE 

ENGINE 

(MIL)

SERVICE 

ENGINE 

SOON