Exhaust Back Pressure (EBP) Sensor

1994 PCED OBDI-A

SECTION 18A: Diesel Diagnosis — 7.3L DI Engine

H: Exhaust Back Pressure (EBP) Sensor
Introduction

Signal Functions

The EBP (exhaust back pressure) sensor is a variable capacitance sensor that when supplied with a 5-volt reference signal from the PCM produces a linear analog voltage signal that indicates pressure.

The EBP sensor's primary function is to measure exhaust back pressure so that the PCM can control the exhaust back pressure device when needed.

Detection/Management

An EBP signal that is detected out of range (high or low) by the PCM will cause the engine to ignore the EBP signal and disable exhaust back pressure operation.

Note

After removing connectors always check for damaged pins, corrosion, loose terminals, etc.

Connector Checks to Ground (B-)
(Check with sensor connector disconnected and ignition key off, all accessories off)
Test Points	Spec.	Comments
A to Grd	<5 ohms	Resistance to ground check with key off. If greater than 5 ohms the harness is open.
B to Grd	>5 ohms	Resistance less than 5 ohms indicates a short to ground.
C to Grd	>5 ohms	Resistance less than 5 ohms indicates a short to ground.

Connector Voltage Checks
(Check with Sensor Connector Disconnected and Ignition Key On)
Test Points	Spec.	Comments
A to Grd	0-.25 volts	If greater than .25 volts signal wire is shorted to VREF or battery.
B to Grd	5 volts	VREF check with key ON.
C to Grd	12 volts	Signal. If greater than .25 volts signal wire is shorted to VREF or battery.

Harness Resistance Checks
(Check with breakout box installed on engine harness only)
Test Points	Spec.	Comments
No. 91 to A	<5 ohms	Resistance from sensor connector to 104 pin connector.
No. 30 to C	<5 ohms	Resistance from sensor connector to 104 pin connector.
No. 90 to B	<5 ohms	Resistance from sensor connector to 104 pin connector.

DTC Descriptions

145 = Signal voltage was less than .04 volts for more than .10 seconds.

146 = Signal voltage was greater than 4.90 volts for more than .10 seconds.

147 = EBP pressure was greater than 71 in-Hg (240 kPaG) for 3 seconds. Check exhaust for restriction and refer to EBP device diagnostics if not an electronic concern.

kPa	EBP (Volts)
0	0
55.16	0.25
137.9	1.45
344.75	4.45
365.44	4.75
413.7	5.00

In Hg	PSI
0	0
16.38	8
40.94	20
102.36	50
108.50	53
122.83	60

H: Pinpoint Tests