POWERTRAIN CONTROL MODULE
Note. For Powertrain Control Module (PCM) connector and terminal identification, see PIN VOLTAGE CHARTS article.
Note. To perform the following ground and power tests, see WIRING DIAGRAMS article.
Ground Circuits
- Disconnect PCM connectors. Using an ohmmeter, check for continuity to ground on PCM harness ground terminals. See «PCM GROUND CIRCUIT TERMINALS»(ref-12136-S29101040172000121100000) table. Resistance should be zero ohms. If not, locate and repair open in wire. PCM GROUND CIRCUIT TERMINALS Vehicle PCM Connector Terminal No. Passport, Rodeo & Rodeo Sport (2.2L) & VehiCROSS (3.5L) White C8 Passport, Rodeo & Rodeo Sport (3.2L) & Trooper (3.5L) Blue F1 .... Blue F40 .... Red S1 .... Red S23 .... Red S40 .... White C9 VehiCROSS (3.5L) White C7
- Reconnect PCM connectors. Using a voltmeter, connect negative lead of voltmeter to a good ground. Backprobe positive lead of voltmeter to each ground terminal. With vehicle running, voltmeter should indicate less than one volt. If voltmeter reading is greater than one volt, check for open, short, corrosion or loose connection on ground circuit. Repair as necessary.
Power Circuits
Turn ignition on. Using a voltmeter, backprobe PCM harness connectors. Check for battery voltage between PCM ignition power terminals and ground. See PCM POWER CIRCUIT TERMINALS table. If battery voltage is not present, check IGN fuse and fusible links. If fuse is okay, check for an open in wire between battery and ignition switch, and between ignition switch and PCM terminal. If okay, check for a defective ignition switch.
| Vehicle | PCM Connector | Terminal No. |
|---|---|---|
| Passport, Rodeo & Rodeo Sport (2.2L) | White | F16 |
| Passport, Rodeo & Rodeo Sport (2.2L) & VehiCROSS (3.5L) | Red | A4 |
| — | Blue | E5 |
| — | Blue | E16 |
| Passport, Rodeo & Rodeo Sport (3.2L) & Trooper (3.5L) | Blue | F19 |
| — | Blue | F20 |
| — | Blue | F57 |
| — | Blue | F75 |
| — | Red | S32 |
| VehiCROSS (3.5L) | Blue | F16 |
PCM POWER CIRCUIT TERMINALS
ENGINE COOLANT TEMPERATURE SENSOR
If a Engine Coolant Temperature (ECT) sensor related code is present, see appropriate SELF-DIAGNOSTICS article.
HEATED OXYGEN SENSOR
If a Heated Oxygen Sensor (HO2S) related code is present, see appropriate SELF-DIAGNOSTICS article.
INTAKE AIR TEMPERATURE SENSOR
If an Intake Air Temperature (IAT) sensor related code is present, see appropriate SELF-DIAGNOSTICS article.
KNOCK SENSOR
If a Knock Sensor (KS) related code is present, see appropriate SELF-DIAGNOSTICS article.
MANIFOLD ABSOLUTE PRESSURE SENSOR
If a Manifold Absolute Pressure (MAP) sensor related code is present, see appropriate SELF-DIAGNOSTICS article.
MASS AIR FLOW SENSOR
If a Mass Air Flow (MAF) sensor related code is present, see appropriate SELF-DIAGNOSTICS article.
THROTTLE POSITION SENSOR
If a Throttle Position (TP) sensor related code is present, see appropriate SELF-DIAGNOSTICS article.
TRANSMISSION TEMPERATURE SENSOR
Note. Transmission temperature sensor may also be referred to as Transmission Fluid Temperature (TFT) sensor.
For diagnosis and testing information, see appropriate AUTOMATIC TRANSMISSIONS article.
TRANSMISSION RANGE SWITCH
If a Transmission Range (TR) switch related code is present, see appropriate SELF-DIAGNOSTICS article. For additional information, see appropriate AUTOMATIC TRANSMISSIONS article.
VEHICLE SPEED SENSOR
If a Vehicle Speed Sensor (VSS) related code is present, see appropriate SELF-DIAGNOSTICS article.
Ignition Control Module
See ENGINE CRANKS BUT WILL NOT RUN in BASIC DIAGNOSTIC PROCEDURES article.
Main Relay
This 4-terminal relay is located in under-hood fuse box. Main relay is used for PCM power control. See appropriate wiring diagram in WIRING DIAGRAMS article for terminal identification.
FUEL SYSTEM
| CAUTION | Relieve fuel system pressure before servicing fuel system components. See FUEL SYSTEM PRESSURE RELEASE procedure in REMOVAL, OVERHAUL AND INSTALLATION article. A small amount of fuel may be released when servicing fuel pipes or connections. To reduce chance of personal injury, cover fuel pipe fittings with shop towel before disconnecting fuel pipes to catch any fuel that might leak out. Place towel in approved container. |
ELECTRONIC THROTTLE CONTROL SYSTEM -TROOPER
See ELECTRONIC THROTTLE CONTROL SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article.
FUEL DELIVERY
Note. For fuel system pressure testing, see appropriate FUEL SYSTEM DIAGNOSIS procedure in BASIC DIAGNOSTIC PROCEDURES article.
Fuel Pressure Regulator
For fuel pressure regulator testing, see appropriate FUEL SYSTEM DIAGNOSIS procedure in BASIC DIAGNOSTIC PROCEDURES article.
Fuel Pump Relay
See FUEL SYSTEM ELECTRICAL TEST in BASIC DIAGNOSTIC PROCEDURES article.
Fuel Injector(s)
Disconnect fuel injector harness connector. Measure resistance across injector terminals. Resistance should be as specified. See FUEL INJECTOR COIL RESISTANCE table.
| Application | (1) Ohms |
|---|---|
| All Models | 11.8-12.6 |
| (1) Injector resistance specification is at 140°F (60°C). | |
| (1) | Injector resistance specification is at 140°F (60°C). |
FUEL INJECTOR COIL RESISTANCE
FUEL TANK LEAK CHECK
| CAUTION | Before attempting fuel tank leak check, place a dry chemical (Class B) fire extinguisher near work area. Before removing fuel tank, ensure fuel hoses and fuel sender gasket are not leaking onto tank. |
- Relieve fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE procedure in REMOVAL, OVERHAUL & INSTALLATION article. Remove fuel tank. Plug filler neck, vent hoses and fuel lines.
- Install short piece of fuel line on fuel tank meter vent tube. Apply approximately 1-1.5 PSI (7-10 kPa) of air pressure to tank through vent tube. Test suspect area with soap solution or by submersion. If leak is found, replace tank.
Idle Air Control Valve
See appropriate SELF-DIAGNOSTICS article.
Ignition Control Circuit
See appropriate SELF-DIAGNOSTICS article.
Knock Sensor Circuit
See appropriate SELF-DIAGNOSTICS article.
Linear EGR Valve
See DTC P0401-P0406 in appropriate SELF-DIAGNOSTICS article.
Common Components
- Fuel tank
- EVAP vent solenoid
- Fuel Tank Pressure (FTP) sensor
- Fuel pipes & hoses
- Vapor lines
- Fuel cap
- EVAP canister
- Purge lines
- EVAP canister cut valve (purge solenoid)
Required Service
The Positive Crankcase Ventilation (PCV) system may require service for obstructions if any of the following conditions exist
- Rough Idle
- Stalling or Slow Idle Speed
- Oil Leaks
- Oil in Air Cleaner
- Sludge in Engine
A leaking PCV valve or hose could cause
- Rough Idle
- Stalling
- High Idle Speed
If engine idles roughly, check for clogged PCV valve and for plugged or broken PCV hoses BEFORE adjusting idle. Check correct PCV valve application to ensure the correct valve is fitted. Replace PCV valve if required.
Checking PCV Valve Function
- Remove PCV valve from rocker cover. Run engine at idle. Place thumb over open end of valve to check for vacuum. If there is no vacuum at valve, check for obstruction in manifold port, hoses or PCV valve. Repair or replace as necessary.
- Turn engine off. Remove PCV valve. Shake valve and listen for rattle of check valve inside PCV valve. If a clear rattle is not heard, replace PCV valve.
- Visually inspect valve for varnish or deposits that may make PCV valve sticky, restricted or incompletely seated. Replace if necessary.
- Engine must be sealed for PCV system to function as designed. If leakage, sludging or dilution of oil is noted and PCV system is functioning properly, check engine for cause and repair as required to ensure PCV system will continue to function properly.
- Since an engine operating without any crankcase ventilation can be damaged, it is important to replace PCV valve and air cleaner breather at regular intervals. Check all hoses and clamps for failure or deterioration.
Brake Light Switch
- Disconnect brake light switch harness connector. Using an ohmmeter, check continuity between brake light switch terminals No. 1 and 4. See WIRING DIAGRAMS article for terminal identification. Continuity should not be present. Depress brake pedal or actuate brake light switch, continuity should be present. Replace switch if not as specified.
- Check for battery voltage at brake light switch connector. If battery voltage is not present, check STOP-HAZARD (20-amp) fuse in fuse box. If fuse is okay, check battery feed wire for an open or short. Repair as necessary.
Brake Light Switch with Cruise Control
Test brake light circuit. See BRAKE LIGHT SWITCH . Using an ohmmeter, check for continuity between terminals No. 2 and 3. Continuity should be present. Depress brake pedal, to deactivate cruise control. Continuity should not be present. Replace switch if not as specified.
A/C Clutch Relay
- Disconnect A/C clutch relay harness connector. A/C clutch relay is located in under-hood fuse/relay box. Using proper mini-schematic and an ohmmeter, check continuity between A/C clutch relay winding terminals. See WIRING DIAGRAMS article. Continuity should be present. Check continuity between clutch drive circuit terminals of relay. Continuity should not be present.
- Using jumper wires, apply ground and battery voltage to relay winding terminals. Continuity should now be present between clutch drive circuit terminals of relay. Replace A/C clutch relay if continuity is not present.