DTC P1297: NO CHANGE IN MAP FROM START TO RUN Dodge Ram Van B2500

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For circuit identification and wiring diagram, see RAM VAN & RAM WAGON wiring diagram in WIRING DIAGRAMS article.

Note. DTC P1297: NO CHANGE IN MAP FROM START TO RUN is monitored with engine speed 400-1500 RPM and throttle closed. DTC may be stored in Powertrain Control Module (PCM) when PCM senses too small a difference between barometric pressure at ignition on and manifold vacuum with engine running for 8.8 seconds. Possible causes are: defective MAP sensor, defective or restricted vacuum ports, defective connectors or defective wiring.

1. Turn ignition on, with engine off. Using scan tool, read DTCs. If DTC P0107: MAP SENSOR VOLTAGE TOO LOW is present, perform DTC P0107: MAP SENSOR VOLTAGE TOO LOW test. If DTC P0107: MAP SENSOR VOLTAGE TOO LOW is not present, go to next step.
2. Start engine and allow it to idle for 30 seconds. Using scan tool, read DTCs. If DTC SPECIFIC GOOD TRIP COUNTER is displayed and displayed count is "0", go to next step. If DTC SPECIFIC GOOD TRIP COUNTER is not displayed or displayed count is not "0", go to step 6).
3. Turn ignition off. Disconnect MAP sensor connector. (Схема №19) Clean and/or repair connector as necessary. Using a voltmeter, check voltage on MAP sensor connector, 5-volt supply circuit (Orange wire). If voltage is more than 4.5 volts, go to next step. If voltage is 4.5 volts or less, repair open 5-volt supply circuit. Perform TEST VER-5A.
4. Turn ignition off. Remove MAP sensor. Inspect MAP sensor vacuum port for restrictions. Remove restrictions as necessary. Perform TEST VER-5A. If no restrictions exist, go to next step.
5. At this time, MAP sensor is assumed to be defective. Replace MAP sensor. Perform TEST VER-5A.
6. Start engine and allow it to idle. Using scan tool, monitor engine vacuum while snapping throttle open and closed. If vacuum drops rapidly to less than one in. Hg, check for restricted or leaking vacuum to MAP sensor. Check for defective MAP sensor or PCM. Repair as necessary. If vacuum does not drop rapidly to less than one in. Hg, go to next step.
7. Start engine and allow it to idle. Using scan tool, set engine speed to 1500 RPM and read MAP sensor voltage. Wiggle connectors and wiring harness from MAP sensor to PCM. (Схема №19) PCM is located in engine compartment. See PCM LOCATION table under SYSTEM DIAGNOSTICS. If engine stall or voltage becomes erratic while wiggling wiring harness, repair connectors and wiring harness as necessary where wiggling caused engine to stall or voltage to become erratic. Perform TEST VER-5A. If engine does not stall and voltage does not become erratic, go to next step.
8. Turn ignition off. Inspect intake manifold and MAP sensor vacuum port and hose for restrictions. Repair restrictions as necessary. Perform TEST VER-5A. If no restrictions exist, go to next step.
9. At this time, MAP sensor is assumed to be defective. Replace MAP sensor. Perform TEST VER-5A.