Pontiac Fiero 1988 Service Manual page 625

6E3-A42 DRIVABILETY AND
EMISSIONS - FUEL INJECTION (PORT)
PORTED
MANIFOLD
V A C U U M
INJECTOR ' P
6-WAY CONN.
TERM D.
N.O.
EGR V A C U U M DIAGNOSTIC SWITCH
7-13-87
"1
TO AIR CLEANER
4*
ASSEMBLY
IGN.
i
J l N J 2
ECM
PNK/BLK
901 GRY/RED
- 9 § 7
D K
mm
450 BLK/WHT
G R O U N D
5 S 1 9 1 4 - 6 E
CODE 32
EXHAUST GAS RECIRCULATION (EGR) CIRCUIT
2.8L "P" SERIES (PORT)
C i r c u i t D e s c r i p t i o n :
The EGE valve vacuum is controlled by an ECM operated solenoid. The ECM will turn the EGE "ON" and
"OFF" (duty cycle) by grounding CKT 901. The duty cycle is calculated by the ECM based on information from
the coolant sensor, MAP sensor, and engine rpm. There should be 0% (NO EGE) when in Park or Neutral, TPS
input below a specified value, or TPS indicating wide open throttle (WOT).
With the ignition "ON", engine stopped, the EGE solenoid is de-energized, unless the diagnostic terminal is
grounded.
Code 32 means that the EGR diagnostic switch was not detected closed under the following conditions:
• Coolant temperature greater than specified amount.
• EGE duty cycle commanded by the ECM is greater than 50%
• Manifold pressure less than 25 kPa, (7"vacuum)
• All conditions above must be met for about 8 seconds
Test D e s c r i p t i o n :
Numbers below refer to circled
numbers on the diagnostic chart.
1. With the ignition on, the solenoid should not be
energized and vacuum should not pass to the EGR
valve.
2. To this point, the EGR solenoid and valve are OK
and the following checks will diagnose the
diagnostic vacuum switch portion of the system.
3. The diagnostic switch should close at about 2" of
vacuum. With vacuum applied, the switch should
close and resistance go to near zero ohms.
D i a g n o s t i c A i d s :
A "Scan" tool can also be used to check the
diagnostic switch circuit. The "Scan" should display
"ON" when vacuum is applied to the diagnostic
switch. The switch should also be indicated as being
closed whenever the ECM is commanding an EGR
duty cycle of greater than 50%. EGE duty cycle can
also be monitored by a "Scan" tool.