Export service from another module in Angular 2

I think you are getting error because you forgot @ before Injectable :

import { Injectable } from '@angular/core';
import { Observable } from 'rxjs/Rx';
import { AttendanceSummary } from './attendance-summary.model';
import { Http, Response, Headers, RequestOptions } from '@angular/http';
import { HttpClientService } from '../core/httpClient.service';

@Injectable()
export class AttendanceSummaryService {

    private apiBaseUrl = '/api/v1/agency/attendances/';
    constructor(private http: HttpClientService) { }
}

For others finding this question. In your module, you may have your service listed in exports. It should be in your providers; not in imports, declarations, or exports.

@NgModule({
    imports: [],
     exports: [],
     declarations: [],
     providers: [export-service-here]
})