[thedungbeetle]

1995 Isuzu Rodeo, 3.2L, 6cyl, 124000+ mi, Auto xmission, 4x4.

I commute about 38 miles each way to work and back. For a while my check engine light would come on close to the end of my trip. In the last week, it has come on around the half way point. Twice since then, it has stalled on me. The first time it happened, I restarted it right away and noticed the check engine light was back out. The second time it stalled (today), I had trouble restarting it and detected a funny smell. When I finally started it, the check engine light was back out again. The problem seems to be getting worse. Please help.

[smj999smj]

Well, the first thing to do would be to check for stored trouble codes. Just because the light is not on currently, does not mean there is not a retrievable code. Here's how to pull the codes:

The provision for communicating with the Engine Control Module (ECM) is the Data Link Connector (DLC) . The DLC is located behind the left "A" Pillar Panel. It is used in the assembly plant to receive information in checking that the Engine is operating properly before it leaves the plant. The Diagnostic Trouble Code(s) (DTCs) stored in the ECM's memory can be read by counting the number of flashes of the Malfunction Indicator Lamp (MIL) when the Diagnostic Test Terminal of the DLC is grounded. The DLC Terminal "1" (diagnostic request) is pulled "Low" (grounded) by jumping to DLC Terminal "3", which is a Ground Wire. This will signal the ECM that you want to "flash" DTC(s), if any are present.

Once Terminals "1" and "3" have been connected, the Ignition Switch must be moved to the "ON" position, with the Engine not running. At this point, the MIL should flash DTC 12 three times consecutively. This would be the following flash, sequence: "flash, pause, flash-flash, long pause, flash, pause, flash-flash, long pause, flash, pause, flash-flash". DTC 12 indicates that the ECM's diagnostic system is operating. If DTC 12 is not indicated, a problem is present within the diagnostic system itself, and should be addressed by consulting the appropriate diagnostic chart.

Following the output of DTC 12, the MIL will indicate a DTC three times if a DTC is present, or it will simply continue to output DTC 12. If more than one DTC has been stored in the ECM's memory, the DTC(s) will be output from the lowest to the highest, with each DTC being displayed three times.

TO ERASE CODES:

When the ECM sets a trouble code, the MIL ("CHECK ENGINE" Light) will come "ON" and a trouble code will be stored in memory. If the problem is intermittent, the light will go out after 10 seconds, when the fault goes away. However, the trouble code will stay in the ECM memory until the Battery positive voltage to the ECM is removed. Removing Battery positive voltage for 30 seconds will clear all stored trouble codes.

Removing Battery positive voltage from the ECM can be accomplished by removing fusible link F13 (30 amp) from the underhood fuse box or by removing the ECM connectors.

Trouble Codes should be cleared after repairs have been completed. Also, some Diagnostic Charts will tell you to clear the DTC(s) before using the chart. This allows the ECM to set the DTC while going through the chart, which will help to find the cause of the problem more quickly.

CAUTION: To prevent ECM damage, the key must be "OFF" when disconnecting or reconnecting power to ECM (for example Battery Cable, ECM Pigtail, ECM Fuse, Jumper Cables, etc.) When using a hand-held diagnostic scanner, or "Scan Tool" to read the DTC(s), clearing the DTC(s) is done in the same manner as in the above procedure.

[smj999smj]

DIAGNOSTIC TROUBLE CODE (DTC) DESCRIPTION



DTC 13 Oxygen sensor circuit open/grounded.
DTC 14A Engine coolant temperature sensor circuit (high temperature indicated).
DTC 14B Engine coolant temperature sensor circuit (low temperature indicated).
DTC 21A Throttle position sensor circuit (signal voltage high).
DTC 21B Throttle position sensor circuit (signal voltage low).
DTC 23A Intake air temperature sensor circuit (low temperature indicated).
DTC 23B Intake air temperature sensor circuit (high temperature indicated).
DTC 24 Vehicle speed sensor circuit.
DTC 32 EGR system fault.
DTC 33A MAP sensor circuit (signal voltage high, low vacuum).
DTC 33B MAP sensor circuit (signal voltage low, high vacuum).
DTC 42 Electronic spark timing (EST) circuit.
DTC 44 Oxygen sensor circuit (lean indication).
DTC 45 Oxygen sensor circuit (rich indication).
DTC 51 ECM or EEPROM failure.

[thedungbeetle]

I didn't find the DLC. If it's in there, it isn't hanging down anywhere like the diagram would lead you to believe. If it's plugged into the ECM, I would rather not arbitrarily start yanking wires out of it without being sure of which one to remove. I'm also unsure of where the Malfunction Indicator Lamp is located.

[md80]

A bad cat could cause that.

[smj999smj]

The DLC is not plugged into the ECM or anything else, for that matter. It's just a plug at the end of a 3-wire subharness. Sometimes they're tucked behind the left side kickpanel.