OUTPUT FUNCTIONS
Injection Pressure Regulator - Is a variable position valve
that controls injection control pressure. The PCM uses many
input variables to determine the desired injection control pressure.
Battery voltage is supplied to the IPR when the ignition key is in
the on position. Valve position is controlled by switching the
output signal circuit to ground inside the Powertrain Control Module
(PCM). On/off time is modulated from 0-50% dependent upon the
desired injection control pressure.
FAULT DETECTION MANAGEMENT
An open or a short to ground control circuit can be detected by an
on demand output circuit check performed during the engine off test.
The PCM is capable of detecting, while the engine is running, if
desired injection control pressure is equal to measured injection
control pressure. If the measured injection control pressure
does not reasonably compare to the desired injection control
pressure, the PCM ignores the measured ICP signal and attempts to
control the engine with the desired value. (If the problem was
in the sensor circuit, this strategy causes little performance
deterioration, if the problem is in the control circuit, engine
performance will probably still be unsatisfactory.)
A faulty IPR or problem with the high pressure oil system can be
detected by the engine running test during the injection control
pressure step test. During this test, the PCM commands and
measures two specific pre-programmed pressures. A fault code
is set, if the pressures can not be maintained.
NOTE: THE ENGINE WILL NOT OPERATE WITH AN IPR CIRCUIT THAT
IS NOT FUNCTIONING.
After removing connector always check for
damaged pins, corrosion, loose terminals, etc.
| Connector Checks to Ground (B-) |
| (Check with IPR Connector Disconnected and
Ignition key off, all accessories off) |
| Test Points |
Spec. |
Comments |
| A to Grd. |
> 1000 ohms |
Resistance to chassis ground, if shorted to ground, #71 or
#97. |
| B to Grd. |
> 1000 ohms |
A short to ground will command full IPR pressure, code 1282
may be set. |
| IPR Voltage Checks |
| (Check with regulator connector disconnected) |
| Test Points |
Spec. |
Comments |
| A to Grd. |
B+ |
Batt. voltage from #71 or #97 check with key on (GP relay
coil is supplied from PCM). |
| B to Grd. |
0 - .25v |
If greater than .25 volts, signal wire is shorted to V Ref.
or battery. |
| Harness Resistance Checks |
| (Check with breakout box installed on engine
harness only) |
| Test Points |
Spec. |
Comments |
| #83 to #71 or #97 |
5 to 20 ohms |
Resistance through entire IPR circuit including regulator,
check with regulator connector connected. |
| #83 to B |
< 5 ohms |
Resistance from 104 pin connector to regulator connector. |
| #71 or #91 to A |
< 5 ohms |
Resistance from power supply, #71 or #97 to regulator
connector |
| Diagnostic Trouble Code Description |
| 1283 |
= |
Output circuit check detected during Std. test, indicates
high or low resistance in circuit, |
| 1282 |
= |
ICP pressure was greater than 3675 PSI (25 MPa) for 1.5
seconds. (possible grounded IPR control circuit.)
(Refer to injection control pressure diagnostics if not
electronic fault.) |
| 1211 |
= |
(1) If set during normal engine operation indicates engine
is operating in open loop control and ICP pressure is above or
below desired pressure. (Refer to ICP control system
diagnostics.) |
|
(2) If set during engine running test, indicates ICP system
failed step test and could not maintain commanded pressure. |
|
