Output Diagnostic Test Mode (DTM)

The CIS-TURBO engine control system has a self diagnostic mode where it actually operates specific output devices in sequence. This allows technicians to check (audibly or with DVM) whether or not certain devices and circuits are working. This "output check" mode is initiated in similar manner as the fault memory display (see DISPLAYING FAULT CODES), except that you start with the ignition turned "off". There are five separate output checks generated in a specific order, each with its own identifying code and separated by an activation step which the technician must manually perform. Once the first output check is initiated, each time the fuse is inserted into the fuel pump relay (or jumper wire connected between test connectors), the next output check is initiated. In this way, if you only wanted to test the idle stabilizer (3rd output check), you can simply step through the other tests.

Output checks will occur in the following order:

1. Code 4433
Fuel pump relay check (tests the ability of the fuel pump relay to turn the pump "on" by deliberately creating an output signal to energize the relay and so the technician can monitor the fuel pump to find if it is turning "on").

2. Code 4441
Oxygen sensor frequency valve (checks operation of frequency valve by deliberately generating a known duty cycle signal so the technician can monitor the valve for correct response).

3. Code 4442
Wastegate frequency valve (checks operation of frequency valve by deliberately generating a known duty cycle signal so the technician can monitor the valve for correct response).

4. Code 4443
Cold start valve check (checks for correct operation of cold start valve when a known signal is applied).

5. Code 4343
Carbon canister shut-off solenoid check (tests solenoid and wiring by deliberately creating an output signal to the solenoid so the technician can monitor it for a response).

6. Code 0000
End of output checks

ACTIVATING OUTPUT CHECKS
After having displayed and recorded all fault codes, use the following procedure to perform output checks.

Diagnostic Connectors - Activating Self Diagnostics:

Fuse/Relay Panel Showing Fuel Pump Relay w/Fuse Receptacle:

1. With ignition turned "off", insert fuse into top of fuel pump relay (or connect terminals of diagnostic connectors with jumper wire, as shown in diagram).

2. Turn ignition "on" but do not start engine. Check engine light (or LED) should light up. Wait at least 4 seconds then remove fuse from relay (or disconnect jumper wire from brown connector). The first output check is now activated. A code 4433 should be displayed. In this mode, the codes are output codes and indicate which device or circuit is being tested.

^ Fuel pump should run while code 4433 is being displayed (listen for "humming" sound from pump, should be audible). If fuel pump does not run, check pump, fuse, wiring and relay individually, after output checks are complete.

3. Remove fuse #13 (fuel pump) or disconnect fuel pump electrical connector. This is done to prevent the fuel pump from running continuously during remainder of output checks. If pump is allowed to run during testing, a rich condition may result causing hard starting after testing is complete.

4. Switch to the next step by re-inserting fuse into relay (or reconnecting jumper wire) for 4 seconds, then remove. The next output check is now activated. Code 4441 should display.

^ Oxygen sensor frequency valve should operate (cycle on and off). A rapid clicking sound should be heard from from frequency valve. If not, refer to specific testing procedures for this device.

5. Switch to the next step. Code 4442 should display.

^ Wastegate frequency should operate (cycle on and off). A rapid clicking sound should be heard from from frequency valve. If not, refer to specific testing procedures for this device.

6. Switch to next step. Code 4443 should display.

^ .Cold start valve should operate (cycle on and off). A clicking sound should be heard from from the valve. If not, refer to specific testing procedures for this device.

7. Switch to next step. Code 4343 should be displayed (carbon canister shut-off solenoid check).

^ Carbon canister shut-off valve should operate. An audible "clicking" should be heard from the canister shut-off solenoid, indicating that the solenoid and circuit are OK. If not, refer to specific testing procedures for this device.

NOTE: If the correct outputs are not obtained, check wiring and connections, repair if necessary. See COMPONENT AND CIRCUIT TESTING for the indicated device and circuit.

If ECU will not enter output check mode, check continuity of wires between diagnostic connectors and control unit. Also check for power at top terminal of black diagnostic connector (should have battery power), and check ECU and wire at bottom terminal of black diagnostic connector for good ground connections. Repair as necessary. If no wiring or power supply problems are found, and ECU still won't enter output check mode, then ECU is faulty.